Category: Dogs

Squamous Cell Carcinoma (SCC)

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Squamous Cell Carcinoma (SCC) is a serious disease, but if caught early enough, there is  much we can do about it. Vigilance on your part is the key to noticing any abnormalities warranting an exam by one of our doctors. It occurs in dogs and cats, although much more often in cats.

There are two predominant versions of this disease; the skin version and the oral version.

The skin version of SCC is caused by excessive amounts of sunshine, so the disease is prevalent here in California. White-haired cats have more than a 13 times greater risk of getting this disease than do cats of other colors, due to their lack of pigmentation.

The oral version of SCC is particularly aggressive, as opposed to the skin version of SCC. 90% of cats with oral SCC are dead within 12 months of diagnosis. Part of this is due to the delay in diagnosis, since cats hide problems, and it is not easy for owners to look into their cat’s mouth.

To help prevent his serious problem from happening in your cat there are three things you can do:

Have us show you how to do an oral exam on your pet during an office call. Our In Home Exam page has more information on performing this exam.

Come in for a yearly Wellness Exam. For older pets, which should examine them every 6 months.

Have your pet’s teeth cleaned, whether it is without anesthesia, called a Non Anesthetic Dental, or under anesthesia. In each of these we perform a complete oral exam.

Graphic photos later on this page

Oral Squamous Cell Carcinoma

This is a particularly aggressive form of the disease that has unique biological behavior. It is also known as Feline Oral Squamous Cell Carcinoma (FOSCC). The oral cavity is a common site for SCC, accounting for 10% of all feline tumors.

The oral version of SCC can occur anywhere in the mouth or jaw.  Under the tongue, called the sublingual area, is where it is found most often. The bone of the jaw is commonly involved, and can be readily seen on a radiograph.

Many other tumors tend to be found in the lungs when they spread from their original location to the rest of the body. This is not the case for oral SCC. If it spreads it is oftentimes found in the submandibular lymph on the same side of the mouth as the tumor.

These tumors grow rapidly, and are usually well entrenched by the time a diagnosis is made. At this stage the prognosis is poor, so early detection is vital. This as another affirmation of the need for complete physical exams in cats, especially as they age. Older cats need frequent exams to catch this disease and other geriatric diseases before they have progressed too far.

The average age of cat with oral SCC is 12 years, although it has been diagnosed in cats much younger. It can occur in most any breed of cat. One year survival rate is less than 10%. Most cats succumb  to FOSCC  2-5 months after diagnosis.

Symptoms

Typical symptoms might include halitosis, difficulty eating (dysphagia), blood from mouth or in water bowl, and drooling. Other symptoms can be subtle and non-specific. These include weight loss, hiding, and decreased grooming.  Oral SCC can be present without any outward signs.

Is postulated that cats exposed to tobacco smoke have an increased chance of getting oral SCC. This is the same for cats wearing flea collars and those that ate canned food as opposed to dry food, especially canned tuna. It is not sure why cats eating dry food has less SCC, possibly because they might have less tartar leading to better oral hygiene. More work needs to be done in these areas to delineate a cause.

This cat has it on its lower jaw (arrow) on the right side. The diagnosis was verified during a biopsy while its teeth were cleaned. SCC can mimic tooth root abscesses, so biopsies are recommended if we suspect it while cleaning your cat’s teeth.

A close up view shows how extensive it is

The radiograph of this cat shows how the cancer has invaded the jaw. There are two areas to note on this view of the lower jaw. The right jaw bone (on the left in the picture) is affected. It has a moth-eaten appearance that can be visualized by comparing it to the left side of the jaw.

Everything within the red circle is diseased tissue. In addition to the bone lesion, the tissue of the mouth surrounding the bone is also affected. This is visualized on the radiograph as the whitish area surrounding the right jaw bone. This is the tissue that was biopsied to confirm the diagnosis. At this stage of the disease the jaw on the affected side needs to be completely removed.

 The only treatment at this point is to remove this side of the whole lower jaw. This is called a mandibulectomy. If the problem is in the tongue, chemotherapy can be used to prolong life. Radiation therapy can be used if the problem is in the upper jaw. Neither treatment is rewarding. We recommend a feeding tube in these cats to aid in their nutrition.

This surgery will be undertaken only if there is no evidence that the tumor has spread by taking an x-ray of the chest and biopsying one of the lymph nodes in the neck. It is an extensive surgery, yet most cats do fine postoperatively. If we do not remove the jaw on this side the problem will not be solved.

Complications can occur after surgery for oral SCC, although most people find them manageable. These complications include difficulty in eating. A feeding tube sometimes needs to be placed if the complications are severe enough. Minor complications might include tongue protrusion and difficulty grooming.

Skin Squamous Cell Carcinoma

In the skin version of SCC, white-haired cats usually get the problem on the ears, head, eyelids and tip of the nose. Cats that are not white usually develop the lesions on unpigmented areas or areas of sparse hair. It occurs mostly in older cats, but the age at which it occurs depends on each individuals’ amount of exposure to sunshine and lack of pigmentation.

Early symptoms of the disease can be subtle, such as a minor irritation or scab on the head, ears, or nose. In more involved cases there is obvious redness, irritation, scabs, and hair loss. These symptoms mimic other diseases, especially skin conditions caused by RingwormSarcoptic mange and allergies, so an accurate diagnosis is imperative.

This tiny ulceration at the tip of this cat’s nose is typical of the subtle lesion that is possible with SCC

The small red spot on this cat’s ear could also be caused from SCC

Diagnosis

It is important to make a correct diagnosis early in the course of the disease because it can significantly affect the final outcome. Diseases that can mimic the oral SCC include:

Tumors

Infections

  • Cryptococcosis
  • Blastomycosis
  • Actinomycosis

Dental Lesions

  • Periodontal disease
  • Endodontic disease
  • Benign growths
  • Polyps
  • Epulis
  • Gingival hyperplasia
  • Eosinophilic granuloma

The primary method of diagnosis for this disease is a skin or mouth biopsy. Any suspicious lesion should be biopsied since the prognosis is much more favorable the earlier the treatment. If we suspect oral SCC we might peform a biopsy or Fine Needle Aspirate (FNA) of a nearby lymph node. Many cats have lesions that are so suggestive of the disease, or the tumor is so large, that we perform surgery to completely remove the tumor at the same time we are doing a biopsy.

Lymph nodes affected with SCC can be normal in size, as opposed to lymph nodes with other cancers, especially lymphosarcoma, that can become substantially enlarged. On another note, an enlarged lymph node in a cat that has oral SCC can be negative for the tumor in the lymph node, so that lymph node is enlarged for some other reason. The bottom line- a physical exam only checking the external lymph nodes by palpation is not adequate to determine spread of the oral SCC. An FNA or biopsy of the lymph node is needed.

Prior to any biopsy we need a blood panel, urine sample, and Felv/FIV tests. Some cats with bone lesions due to SCC will have a high calcium level (hypercalcemia).

Most SCC’s do not spread throughout the body, but they can recur at the site of the original lesion. Those that do spread will go to lymph nodes and the lungs. Prior to any treatment it is important to take a blood sample, a chest x-ray, and a sample of lymph node tissue for analysis. This helps stage the disease and let us know what the proper treatment regimen should be. All cats with this disease must be tested for FeLV and FIV

This is the radiograph of a dog that has cancer that has spread to its chest. The arrows point to small white areas that are the actual tumor masses that are in the thorax. They lodged here after spreading via the bloodstream from the original tumor located elsewhere in the body.

Treatment

Cats with SCC, especially the oral version, are in pain and can be in poor nutritional state. We determine this by a physical exam with a routine blood panel examination. Before any surgery we institute pain control and supplemental feeding, including a feeding tube if necessary.

The advent of the carbon dioxide laser in our hospital has made both of these surgeries more manageable and less painful for our patients.

Skin Squamous Cell Carcinoma is a malignant cancer that needs immediate and aggressive therapy if we hope to arrest it. The primary treatment method is surgical for the skin and oral versions. It involves removal of the affected area or partial amputation of the ear or ears. Treatment with chemotherapy or radiation are unrewarding.

If the lesion is on the nose or head, a great effort is made to preserve a cosmetic look. Again, this emphasizes the need for an early diagnosis. If the lesion is on the ear then a partial amputation of the ear is performed. It is important to remove a significant amount of the ear because recurrence is common if the amputation is incomplete. The redeeming part of this surgery is the fact that most cats look cute when healing is complete.

Some SCC lesions are very extensive. In a case like Ashley’s, we have to amputate almost the whole external ear due to the extensive nature of the lesion. We prefer to care for these situations long before they become this extensive.

This cat, under general anesthesia and ready for surgery, has been positively diagnosed with SCC on both of its ears, even though the problem only seems minor compared to Ashley. The small amount of redness and the minor scabs are the only apparent lesions. 

The following pictures are from an actual partial ear amputation that we performed at our hospital. 

Since it is impossible to determine just how far the tumor has spread, wide margins are cut to minimize the potential for recurrence

The delicate suturing of the ear takes the most time in this procedure. The cosmetic appearance when healing is complete makes the time invested well worth it. Before your pet wakes up from anesthesia we will give it pain medication to minimize discomfort.

We also use the Companion Laser after surgery to minimize swelling and discomfort. In this picture it is being used after a spay (OVH) surgery. 

This is the appearance of the ears immediately after surgery. Within 7-10 days these sutures will be removed.

Four weeks later this is the final appearance. Many people do not even notice that any surgery has been performed. It is important to keep this cat out of the sunshine indefinitely.

We routinely perform this surgery using the carbon dioxide laser. The significant advantages are minimal bleeding during the surgery, negligible post operative pain, and no need to put sutures in for some cases.

The laser is very specific in how it performs surgery, and is specifically calibrated for each procedure.

You can see how it checks its circuits and is calibrated in this video

SSC can occur in other locations, and in other species besides cats. Dogs can also get SCC, although we don’t see it in the mouth and ears as often as we do in cats.

This limping dog has SCC at its toe (arrow). You can see how the bone is being destroyed. Phalanx #2 and #3 are involved.

We amputated the toe all the way up to the metacarpal joint using the laser. The arrow points out where the toe used to be. This radiograph looks different from the one above because it was take immediately after surgery and there was a bandage on the foot. This dog walked out after surgery pain free, partly because we did the surgery by laser, partly because the painful toe is gone.

Additional Treatment Regimens

Radiation therapy using Sr-90 is sometimes used on cutaneous SCC of the nose and ears.

A drug for Mast Cell Tumors (MCT) called Palladia (Toceranib phosphate) has shown some promise in survival time. Further studies are needed to see if this pans out.

NSAID’s (Non Steroidal Anti-inflammatory Drugs) like Metacam (Meloxicam) have been shown to be beneficial in post operative pain and swelling of oral squamous cell carcinoma (FOSCC). These cats eat and feel better, so they are worth it to use if needed.

Care must be taken to make sure the kidneys are not in failure before use of this drug. If chronic kidney disease is present it still might be worth using Meloxicam, since these cats will perish from the FOSCC problem long before the kidney problem in most cases.

A potential treatment for SCC is called Photo Dynamic Therapy. It involves the use of a laser beam to selectively destroy cancerous tissue only. An injection of photosensitive chemical is given to a pet that has SCC. The only cells that absorb this chemical are the cancerous ones. It is only these cells that are destroyed by the laser, the laser beam harmlessly passes through the normal cells that do not absorb the photosensitive chemical. If one of our doctors feels that this therapy is appropriate, they will let you know. It is considered experimental therapy, and is performed locally at the Beckman Laser Institute at the University of California at Irvine, on a referral basis only.

Prevention

The best method of prevention for skin SCC is to eliminate exposure to sunshine. The use of sun block on the tip of the nose and ears is helpful if your cat does not lick or rub it off. White haired cats should be kept indoors, and should be prevented from sunbathing for long periods of time in the window. Even though windows filter out ultraviolet radiation, they do not filter enough of the radiation in the case of SCC.

Older cats need exams at least every 6 months to aid in the early diagnosis of the other forms of SCC, especially the oral form. Careful observation of your cat’s habits as it gets older is important for FOSCC, along with many other geriatric diseases.

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Canine Fractured Tibia (shinbone)

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Some fractures are so severe they require the expertise of a specialist in bone surgery. We have a specialist in bone surgery that will come to our hospital and perform the repair. This has several advantages, not the least of which it costs less than if we refer the repair to a surgical specialist at his hospital. These pictures show the repair of Dakota, a Labrador who fractured his tibia (shinbone) by playing.

Type of Fracture

This fracture is called a spiral fracture due to the winding nature of the crack. The fracture is much more severe than is apparent on this x-ray. What is not apparent on the x-ray are the numerous bone fragments that were found surgically.

Surgery

The following area contains graphic pictures of an actual surgical procedure performed at the hospital. It may not be suitable for some children (and some adults also!). Click here if you would like to bypass the surgery pictures and view post operative x-rays.

Our surgeon needs to utilize specialized equipment if he is to put this bone back together so that Dakota can return to normal function. In this picture he is using magnifying glasses and special lighting. In addition, he has orthopedic instruments and equipment without which he would never be able to repair such a severe fracture.

Bone infections can be serious so significant time is spent in sterile preparation. When Dakota has been anesthetized, and adequately prepared, an incision is made on the inside of his leg. This area has minimal muscle over it and gives good exposure to the fracture site.

After careful dissection and control of hemorrhage the main fracture segments are isolated.The surgeon uses special wires called cerclage wires to begin the process of holding the fracture segments in place. It is a tedious process that takes up a significant amount of the surgery.

The wire is tightened down with a special instrument that gives just the right amount of tension. Too little tension and the wire is useless, too much and the bone fractures even more.

At this point 2 cerclage wires have been applied to the fractures at the top, with new ones being applied to the fractures at the bottom

Eventually 6 cerclage wires are applied to align the bone fragments. Even though these wires are strong the bone will not stay in place and heal with just these wires. A bone plate is needed for most of the stability.

After the bone plate is measured and bent to the specific shape of this tibia, holes are drilled into the bone with a special air powered drill. They have to be drilled to the proper depth and angle or the bone will fracture more or the plate will fail.

Drilling the holes is the first step in the application of the plate. The depth of the holes is measured, and specific screws are used. Some screws compress the plate to the bone, others hold the plate in place.

Two hours from the start of the surgery the plate has finally been applied. We will not remove it unless there is a post operative complication.

The muscle is sutured to preserve its function and to cover the plate. These sutures will slowly dissolve over several months.

The skin sutures will stay in for 2 weeks. at this point in the surgery Dakota is given an antibiotic injection along with a pain injection. after one nights rest in the hospital he will go home. He will need to be confined for one month for healing to progress.

Before Dakota is fully awake from anesthesia an x-ray is taken to assess the surgery. The bend to the plate can be seen, along with the cerclage wires and the different lengths of the various screws. The fractured fibula (arrow) will heal by itself.

Once our surgeon is satisfied that everything is in order Dakota is given a pain injectionand awakened from anesthesia. He will spend the night with us so that he can rest and so we can monitor his recovery. He will need to rest at home for several months before the healing is complete. We will not take the plate out unless complications arise.

One month after the surgery we took an x-ray to make sure the plate is holding well and the bone is healing. If you look carefully, the small bone in the leg, called the fibula, is healed (arrow). Compare it to the x-ray above where you can see the fractured fibula.

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Mast Cell Tumor

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Up to 20% of dogs will get a malignant Mast Cell Tumor (MCT) in their lifetime, making it the most common tumor we encounter in dogs. Other names for MCT are mast cell sarcoma, histiocytic mastocytoma, and mastocytosis.

This disease has a cutaneous form (skin) and a systemic form (internal organs).  The cutaneous form is more prevalent, and is sometimes referred to as the “great pretender” because the skin growth appearance is so variable.  What might seem like just a minor swelling or inflamed area can be a highly malignant cancer. It might also be called the “great fooler” because most people underestimate the problem.

MCTs have the potential to be highly malignant and their treatment needs to be thorough and comprehensive in order to minimize the chance of spread and premature death of your pet. In almost every case the treatment of choice is surgery to remove the tumor. After surgery additional treatment might be indicated.

This page will give detailed information on MCT in the dog since that is the primary species that gets this disease. We occasionally see MCT in cats and ferrets. MCT are second most common tumor in cats. They behave somewhat differently in our feline friends. We will go over MCT in the cat at the end of this page.

Throughout this page are links to numerous other areas on the LBAH web site to give you additional information on that specific topic.

There are some mild surgery pictures in this page showing the open skin after a MCT has been removed. They are suitable for most viewers.

Physiology

Mast cells, also known as mastocytes, originate in the bone marrow and live for weeks to months. Once produced by the bone marrow they circulate through the body ending up in large numbers in the connective tissue of the body, lymph nodes, under the skin, and in internal organs.

Mast cells surround nerves and blood vessels, and are oftentimes found at the interface between the environment and the pet. This means they tend to be found in higher numbers under the skin and the lining of the respiratory system and digestive systems. They play a role in wound healing and defense against invading bacteria, and are a big part of the immune system. They have binding sites on them for the immunoglobulin called IgE. This immunoglobulin is a big part of the immune system when it comes to allergies. You can learn more about it by linking to our allergy page.

Mast cells have the potential to release several different compounds, the most important of which are called vasoactive amines. Vasoactive amines are nitrogen-containing compounds that act on blood vessels. The more important vasoactive amines are histamine, heparin, serotonin and prostaglandin. Histamine is the most important one in relation to MCT.

Histamine goes to the stomach lining and stimulates the secretion of gastric acid. Histamine also dilates blood vessels and increases permeability of the blood vessels, leading to swelling (edema). This mechanism is part of the normal inflammatory process.

Release of large amounts of histamine from a mast cell can result in ulceration or perforation of the GI tract (stomach and intestines) causing pain, hemorrhage, delayed wound healing, shock, and dark blood in the stool (melena). A significant number of dogs with MCT that are necropsied (autopsied) after death have ulcerations in the stomach.

This release of excess histamine is called the paraneoplastic syndrome. It is serious and needs to be addressed prior to and after treatment. This is why any skin growth needs to be handled gently in case it is a MCT and histamine gets released in an excessive amount.

When excess secretion of histamine occurs and only affects the skin it is sometimes known as Darier’s sign. You will notice raised and red areas of the skin when this happens.

In young animals the disease might spontaneously resolve. This is not something you should count on though. This cancer in dogs is unpredictable and can be extremely aggressive, so waiting to see if it resolves is not a good option. Every MCT should be treated as potentially malignant. MCTs can mimic other tumors, making it impossible to identify them simply by appearance.

 Tumor Behavior

As a general rule, benign MCT will be slow growing, well circumscribed (their margins are easy to feel), non-painful, not attached to the underlying tissue, and exhibit minimal inflammation. They might be irritated if your dog or cat is licking at them.

Malignant tumors tend to grow more rapidly, might be ulcerated or painful, have poor margins to determine where they begin and end, are fixed to the tissue below, and may have spread to nearby blood vessels and lymphatic tissue as evidenced by enlarged peripheral lymph nodes.

If the MCT spreads to the internal organs (called systemic mastocytosis) it usually goes to the liver, spleen, lymph nodes, or even back to the bone marrow.

In dogs most MCT are usually found on the trunk and perineum, sometimes on the limbs, and occasionally on the head or neck. MCT of the perineal and inguinal regions tend to behave more aggressively than their tumor grade would predict. Some dogs get multiple tumors.

Mast cell tumors that are large (more than 4 cm), on the face, muzzle, and oral cavity tend to have a poor prognosis.

Mast cell tumors located in the perineal region (anus, scrotum and vulva) may be may be more difficult to remove completely. They might need additional surgery or radiation and chemotherapy.

Dogs that have signs of gastrointestinal ulcers (vomiting, poor appetite, lethargy, or black stools) generally have a poor prognosis. Tumors that recur soon after surgery have a poor prognosis.

You cannot tell definitively whether any skin inflammation is a tumor or something else, and if it is a tumor, whether it is benign or malignant, just by looking at it or feeling it. Microscopic analysis by a veterinary pathologist is the only way to confirm this diagnosis. When we take a tiny sample of cells with a needle (called a fine needle aspirate- FNA) we call this cytology. When we take a large piece of tumor, or even the whole tumor, we call this histopathology.

Cause

There are several factors that contribute to this problem that include genetics, hormonal, environmental, and immune influences. There is suggestion that MCT are related to red or golden hair coats, allergies, or viruses. None of this has been proven at this time.

As is the case with many cancers it is a genetic mutation that is the originating factor. A tumor suppressant gene (called p53) can mutate and is suspected to cause MCT in 50% of the canine cases.

A gene named C-Kit can mutate, leading to excess production of a protein called Kit, which can cause excessive stimulation of mast cells.

Diagnosis

Diagnosis is made based on the Diagnostic Process we utilize in call cases. This includes:

  • Signalment- species, breed, reproductive status, and age.
  • History- observations of the problem you make at home, along with diet, environment, medication, and past medical history
  • Physical exam- Abnormal and normal findings on our exam
  • Diagnostic tests- used to rule in our rule out certain diseases
  • Response to treatment- Does your pet improve when we treat it

For more detailed information on the Diagnostic Process follow this link .

1. Signalment

MCT’s occur in both males and females, typically around 8 years of age or older, although they have been seen in dogs much younger.

This is one of the few diseases that might occur in mixed breed dogs as much as purebred dogs. Certain breeds have a higher incidence though:

  • Boxers
  • Pugs
  • Boston Terriers
  • Labrador Retrievers
  • Beagles
  • Schnauzers
  • Bulldogs
  • Bull terriers
  • Basset hounds
  • Weimaraner
  • Golden retrievers
  • German shorthaired pointers
  • Scottish terriers
  • Shar peis
  • Rhodesian ridgebacks

In cats it is the Siamese breed that has a higher incidence. There is no difference in occurrence rates between males and females.

 2. History

The most consistent symptom of pets with MCT is a growth somewhere on the skin when grooming or petting. Multiple growths are possible, but in most cases it is one skin growth that is found. It might be tiny and barely inflamed, or it might be large and firm. Some pets will be oblivious to the tumor, while others might lick or chew at it. Many MCT wax and wane, which can make pet owner’s think the growth is not important. This waxing and waning can go on for months.

Other symptoms depend on whether heparin or histamine is being released (the paraneoplastic syndrome). In this case a pet can be vomiting, have a bleeding disorder (coagulopathy), have stomach ulcers, blood in the stool (melena), poor appetite (anorexia) or no appetite, abdominal pain, or literally be in shock.  Some symptoms will look as if your pet is having an allergic reaction and require immediate veterinary care. In pets that have spread of MCT to other parts of the body there might also be weight loss.

The following pictures are all MCT’s. As you will see they can vary considerably, so just looking at a skin tumor will not give you a diagnosis. Basal cell tumors, histiocytomas, soft tissue sacromas, and lipomas can all look like mast cells at times.

 This is a close up of a 2.5 cm mast cell on a dog’s side

This large mast cell is on the back of a dog’s leg seen as it is being prepped for surgery

Above the vulva

A large MCT on a dog’s upper eyelid. To help you get your orientation this is the left eye and the dog is facing to the left.

For curiousity sake this is the same dog immediately after surgery

On the skin of the rear leg

Another close up of a MCT on the side

The white arrows are pointing at a MCT on a dog’s scrotum

The black arrow points to an almost imperceptible area that is slightly red and raised. This is a MCT

3. Physical Exam

A complete physical exam is performed on every pet brought to us for a skin growth. There are a multitude of reasons why check other body organs and not just the skin growth you noticed at home:

  • So we do not miss other skin growths that might also be present and that are small or hard to detect. These might be other MCT, lipomas, or squamous cell carcinomas, for example.
  • To ascertain any spread of tumor to lymph nodes. We check the following peripheral lymph nodes during our exam:

o   Submandibular

o   Pre-scapular

o   Axillary

o   Inguinal

o   Popliteal

For more information on where these lymph nodes are located and their role in the immune system follow this link. Our doctors will gladly show you how to palpate them for an in-home exam.

  • To look for other problems that might be present but not obvious. Common ancillary problems in pets that get MST include dental diseasearthritiskidney diseaseliver diseaseheart disease (a heart murmur might be detected), skin allergies and even obesity. It is important that we address these issues for a successful outcome when treating MST.
  • To make sure the pet is ready for any anesthesia in the future

Care must be taken not to palpate a suspected tumor too vigorously because if it is a MCT it can degranulate and release histamine.  At the least it might cause the skin growth to become more inflamed (Darier’s sign), and in the worst case it will cause your pet to go into an allergic reaction and shock if excess histamine is released from the MCT. This is a rare occurrence but something to keep in mind as you touch any specific growth on your pet’s skin.

4. Diagnostic Tests

Routine blood panel, urinalysis, and fecal exam are needed in every case prior to any treatment. These tests give us a detailed picture of your pets overall health status and look for other problems that are not obvious during the physical exam. Finding other problems in pets that present for just a skin growth is a situation we encounter more often than you might think. Heartworm and FeLV/FIV status needs to be know also.

The results of a normal blood panel on a dog that prior to mast cell tumor removal. Sometimes we will see anemia due to blood loss from an ulcer in the GI tract.  We might also see an increase in liver enzymes if the MCT has spread to the liver, and also an increased BUN (Blood Urea Nitrogen) if there is GI bleeding.

We take special pre-anesthetic precautions on older dogs undergoing mast cell surgery. One of those precautions is an EKG to make sure the heart is ready for anesthesia. This is the same dog as the blood panel above, and is a normal EKG.

A very important test to diagnose any skin tumor is called a final needle aspirate (FNA). In this test we take a tiny needle and syringe and obtain some cells from the mass. The test is easy to perform, feels like a pinprick, and does not require anesthesia. It is similar to giving a vaccine, but in this case we are not giving something, we are taking something.

The small number of cells obtained from an FNA are put on a microscope slide and sent to our pathologist. They know why we are sending the sample to them and they specifically look for any signs of a benign or malignant tumor. Due to the high incidence of MST they look for these cells specifically. Pathologists are experts at analyzing cells under a microscope and they will come to one of the following conclusions:

  • They will tell us what cells the aspirate is made of and recommend appropriate treatment.
  • They will give us an idea of what different cells might be involved but have no specific diagnosis
  • They will not be able to tell us anything because of too few cells in the sample or the cells are not identifiable.

This is what a pathologist is looking for under the microscope for a FNA. The arrow points to a clump of 3 mast cells that have been stained to stand out.

Here is a typical report from a FNA on a dog with MCT

Even though no guarantee can be given to the usefulness of the FNA, it is worthwhile in almost all cases because the potential to give us useful information is high, especially when you consider the ease of obtaining the sample.

Knowing whether we are dealing with a MCT ahead of surgery is important because these tumors need aggressive surgery to be certain we remove the complete tumor. If we know going into surgery that we have a MCT we will take at least 3 cm margins around the visible mass. We will also dissect down to a deeper fascial plane to make sure no tumor remains after surgery. This type of aggressive approach is usually not needed in other skin tumor surgeries.

A pre-surgical radiograph is indicated in many cases to look at the thorax and abdomen looking for any spread of the MCT from the skin to the internal organs (systemic mastocytosis).  In addition, a radiograph is indicated any time we anticipate anesthesia and surgery.

We might seen an enlarged sternal lymph node in the chest if the MCT has spread.  The white arrow points to the location where the sternal lymph node resides.

This crescent shaped organ under the black arrow is a big liver, called hepatomegaly, on a radiograph. A MCT is one of several causes to an enlarged liver.

This is a large spleen, called splenomegaly, on a radiograph.

If an abnormality is found on the physical exam, or any diagnostic test, an ultrasound might also be needed. If we see an enlarged liver or spleen prior to surgery we will perform an ultrasound. This is what a spleen looks like during ultrasound

Here is the report on the normal appearing dog spleen above. There is no sign the MCT has spread to the liver or spleen.

DESCRIPTION:

Cellular slides consist of a heterogenous lymphoid population and a few scattered aggregates of stromal connective tissue/splenic trabeculae against a hemodiluted background. Small mature lymphocytes predominate followed by a low number of intermediate lymphocytes and large lymphoblasts. A few metarubricytes, mature plasma cells, and macrophages noted. Nor organisms or atypical cells seen.

MICROSCOPIC FINDINGS:

Spleen consistent with normal or hyperplastic lymphoid tissue

This is an enlarged spleen with nodules that could be caused by a MCT, although there are other causes to this also

If a regional lymph node is enlarged or draining we will perform an aspirate to determine if the tumor has spread. We can also aspirate the bone marrow looking for mast cells.

Information from all these tests is used as part of the surgical plan. It is also used to determine prognosis after surgery once the final tissue sample has been analyzed. If it looks like there has been the spread of tumor to an internal organ then chemotherapy or radiation therapy might be indicated in addition to surgical removal of the mass.

Surgical Treatment (surgery pictures in this section)

The overwhelming majority of MCT are treated with surgery. Microscopic tumor cells that are not visible or palpable can occur, so we remove a margin of 3 cm from the edge of the visible or palpable tumor. We also dissect deep down into the tissue for another 3 cm. This is problematic on tumors of the face, neck, and extremities. In those cases radiation and chemotherapy might be more appropriate.

It is not unusual to perform more than one surgery, especially if the tissue report (histopathology) reveals that we did not remove all of the tumor. This is referred to in the report as the margins not being clean. We like to have 10 mm margins to feel comfortable that we removed all of the tumor. When in doubt a second surgery is indicated to remove any suspected tumor remnant.

We use the laser for all of our MCT surgeries because of the dramatic reduction in bleeding during surgery, along with substantial reduction in swelling and pain after surgery. In the picture our surgeon is gently holding the mast cell between his fingers as he dissects with the surgical laser.

The tumor has been completely removed (notice the lack of bleeding) and what you are seeing is the fat layer under the skin. Notice how large the incision is. This is because we took 3 cm margins on all sides of the tumor, and also because the skin is under tension and spreads wide open when we remove the tumor.

In most cases we need to go deeper than this fat layer and get right down to the muscle layer. At this point we feel comfortable that we have gone 3cm deep into the tissue and have removed all of the tumor that is not visible or palpable.

The piece of sking with the MCT in the center after removal

 

MCT surgical sites sometimes heal poorly due to the disruption the cancer cells cause in the area. This fact, added to such a large incision, has the potential to heal poorly due to the tension on the skin. It is imperative that your pet wears an e-collar and you follow our postoperative instructions.

During the surgery we might also perform an aspirate or biopsy a lymph node in the region of the skin mass to look for spread of the tumor.

Gentle tissue handling is important when obtaining a fine needle aspirate and during the actual surgical procedure. Mast cells can release histamine during these times, so in addition to gentle handling we might put your pet on prednisone, Benadryl, and Pepcid AC prior to, during, and after surgery to minimize the release of histamine and its serious effects on the stomach and intestines.

In the rare cases where surgery might not be feasible, or the tumor is not completely removed, treatment can include medical therapy, radiation therapy, and chemotherapy.

Tissue Analysis and Prognosis

Analyzing the removed tumor tissue after surgery, called histopathology, is crucial to confirm the diagnosis, determine if more surgery or treatment might be needed, and to make a long term plan. The pathologist will let us know if the entire tumor was removed, what grade the tumor is, and what is the mitotic index of the tumor. This is a typical report on a dog with MCT:

SOURCE– 5 cm skin biopsy of mass on left flank

DESCRIPTION

 Examined is a section of skin and subcutis. The section contains a moderately well-dilineated, loosely cellular, unencapsulated dermal and subcutaneous neoplasm. Neoplastic cells are generally round and characterized by round to oval nuclei with moderate variation in nuclear size and chromatin pattern, and moderate to abundant amount of pale amphophilic to deeply basophilic granular cytoplasm. These cells infiltrate between resident collagen fibers, and are accompanied by low numbers of mature eosinophils. The mitotic index is 1. There is multifocal collagenolysis and eosinophil degranulation throughout the mass.

MICROSCOPIC FINDINGS–  Grade 2 mast cell tumor, well-differentiated, mitotic index 1.

PROGNOSIS– Fair to guarded

COMMENTS-Local excision appears to be complete with margins of 1.3 and 1.0 cm on either side, and 0.4 cm deep. Within the sample submitted there is at least one fascial plane deep to the tumor.

Grade 1 MCT are what is called well-differentiated and are usually benign. Grade I MCT occur in 30% – 50% of dogs.  Up to 90% of dogs are cured by surgery alone.

Grade 2 MCT are intermediately-differentiated and might be benign or malignant. In other words, they are unpredictable. Grade II MCT occur in 25% – 55% of dogs. Mean survival time after surgery is 28 weeks. Radiation therapy following incomplete removal can cure over 80%. Chemotherapy is sometimes used in addition to radiation therapy.

Since these tumors can go either way more information is helpful to determine the next course of therapy if at all. This is where the mitotic index comes in to play.

Grade 3 MCT are poorly differentiated and usually malignant. Grade III MCT occur in 20% – 40% of dogs. Mean survival is 18 weeks with surgery. Post-operative chemotherapy and/or radiation therapy might prolong survival.

Mitotic index is another predictor of biological behavior of MCT. Mitotic Index is an indirect measure of cell division. It is measured as the number of mitotic figures per 10 high-powered fields (a high powered field is 400x) when using a microscope.

These grading systems are the best way to determine the individual behavior of the MCT we remove from your pet and its prognosis. Nature is complicated, and unfortunately, not all MCT fit into these orderly classifications, so thoroughness of treatment and vigilance for recurrence are important.

In addition, histopathology is an art and a science, so a pathologist that might assign a specific grade to a tissue sample might not be consistent with another pathologist. Because of this no guarantee can be given to any of these prognostic indicators.

Different studies give varying statistics on prognosis. According to the Veterinary Cancer Group in Tustin, CA the prognosis is as follows:

Grade 1 tumors have a 5-67% chance of recurrence at 12 months.

Grade 2 tumors have a 50% chance of recurrence at 10 months. 88% of dogs with Grade 2 tumors that are incompletely excised and undergo radiation are disease free at 5 years.

Grade 3 tumors have a 94% chance of recurrence at 12 months.

Dogs with a mitotic index of 5 or less had an average survival time after surgery of over 70 months. Those with a mitotic index of greater than 5 had a survival time of less than 2 months, no matter what grade of tumor it is.

Another study showed that 83 percent of dogs with a Grade I MCT, 44 percent of dogs with Grade II and 6 percent of dogs with Grade III were living 1500 days after surgery.

In another study, 100 percent of dogs with a Grade I MCT, 44 percent of dogs with Grade II and 7 percent of dogs with Grade III were living two years after surgery.

Radiation and chemotherapy may be used following surgery. Even if the MCT is not completely removed, 90 percent of dogs that received radiation following surgery for Grades I and II MCTs survived for at least three years.

Medical Treatment

Medical treatment is usually used when surgery is not feasible. Prednisone, a very common and effective corticosteroid (cortisone), can help in some cases when used judiciously and monitored for side effects.

Chemotherapeutic drugs are sometimes used in dogs, especially if the tumor has spread. Common drugs include:

  • Lomustine
  • Masitinib
  • Palladia
  • Vinblastine
  • Torcerinib

Palladia is a kinase inhibitor which blocks the excessive production of the kit protein. It is FDA approved to treat MCT in dogs and is getting lots of hype. It is not a panacea, and when it does work (around 40% of the time), the response is for around 3 months.

Use of chemotherapeutics should never be undertaken without consultation with a veterinary oncologist. These drugs are powerful and need to be monitored for potential side effects. They also cost more than the other medications we routinely use.

Additional Therapy

As is the case with every disease, proper nutrition, access to fresh water at all times, parasite control (both external parasites like fleas and internal parasites like roundworms), exercise, and lots of TLC cannot be overlooked. In our older pets particular attention needs to be paid to the debilitating effects of arthritis, dental disease, and chronic organ disease. Hill’s makes a Prescription Diet for cancer patients called n/d that nourishes the patient without nourishing the cancer cells.

Long Term Care

Even if we completely remove a MCT there is up to a 17% chance another one will appear during your dog’s lifetime. Vigilance and early detection is of importance. Run your hands over your dog’s body at least several times per week for any problems. If you find any mass or growth we need to do an immediate FNA (Fine Needle Aspirate) looking for mast cells. We will teach you how to palpate the more obvious external lymph nodes as an additional monitoring technique.

Any pet that has been previously diagnosed with a MCT should be examined every 3-6 months. This exam should also include a blood panel, urinalysis, fecal exam, radiograph, and abdominal ultrasound.

Feline Mast Cell Tumor

MCT are the second most common tumor in the cat. Even though the basics are the same, MCT’s in cats behave differently than dogs. Cats get a skin form (called cutaneous) and what is called a visceral form (internal). It is possible for a cat to get both forms. They tend to get systemic mastocytosis more commonly than dogs.

There is no correlation to FeLV or FIP in cats that develop MCT. Siamese cats might be genetically predisposed because of a greater occurrence in this breed.

In the cat the grading system used for dogs does not apply regarding prognosis. Some are benign and some are malignant, and spread of the tumor (metastasis) can occur.

Cutaneous Form

The skin form of the feline MCT occurs around the head, eyelids and neck. Lesions can look like almost any growth, although they tend to be solitary, hairless, and raised. Lesions could be multiple, although the presence of multiple lesions does not necessarily mean a poor prognosis. Cutaneous MCT in the feline is usually benign, and for the rare times it does spread, it will go to regional lymph nodes, liver, spleen, and bone marrow just like in the dog.

Visceral Form

The visceral from of MCT usually occurs in the spleen first, then less commonly in the liver or intestine. MCT is the 3rd most common intestinal tumor in the cat after lymphoma and adenocarcinoma.

Typical symptoms in a cat with visceral MCT are vomiting, poor appetite, lethargy, and weight loss. These are the same as the dog and relate back to histamine release in excess.

During a physical exam one of our doctors might palpate an enlarged liver or spleen, abdominal fluid (ascites) or even a mass.

Treatment

Treatment of choice in both forms is surgical removal. If the pathologist report says tumor margins are not clean we can perform the surgery again or do radiation therapy.

The spleen is a common organ for visceral MCT in the cat. This is a normal spleen during surgery.

Prognosis

Prognosis of mast cell tumors of the skin is usually excellent and surgery is generally curative.

Prognosis of mast cell tumors localized to the spleen is good and many live for an additional one to two years after the spleen is removed.

Prognosis is guarded if the mast cell tumor is located in the gastrointestinal tract.

A good prognostic indicator in the cat is appetite when first examined. Those eating well tend to live much longer.

We have a case study of a cat (her name is Ruby) that had intestinal mast cell tumor. The case study covers this cat’s diagnosis and treatment from beginning to end, with pictures of surgery. Here is the link.

Cancer Specialists

When we treat a case of MCT (or any malignant tumor) we routinely refer the case to the Veterinary Cancer Group. They are experts on cancer in animals and provide the latest treatment available. Any time we diagnose and treat a dog or cat with MCT (or any malignant tumor) we recommend you go to them for a second opinion. They will review all data and set up a long-term plan. They are also able to provide chemotherapy and radiation therapy.

This email was sent to us through the LBAH email system. It is typical of the feedback we receive from clients sent to the Veterinary Cancer Group.

Below is the result of your feedback form.  It was submitted

on Thursday, August 11, 2011 at 10:25:07

Name: Leslie

location: Anaheim, CA

Dear Long Beach Animal Hospital,

I just wanted to thank you for everything you’ve done for Bijou and me over the years.  There are no words to express my gratitude to you and your staff.  Bijou is still going through chemotherapy.  Realistically, I know that she doesn’t have very much time left, but she has more good days than bad and, thankfully, seems oblivious to the drama that surrounds her.

I’m also writing to let you know how happy we are that you led us to the Vet Cancer Group in Tustin.  We are seeing Dr. Jarrod Vancil.  He is an incredible vet–knowledgeable, candid, and compassionate with both dogs and their owners.  I feel so fortunate to have him as our oncologist during this difficult time.  At each visit, he provides chemotherapy for the dogs, but he also provides reassuring and much-needed “therapy” for me, the owner.  I just wanted to pass along this information.  The staff at the Vet Cancer Group is also amazing, much like the staff you have at LBAH.  Bijou does not exhibit the fears and anxiety that she did when we were going to the other cancer center.  The staff goes out of their way to make people and animals as comfortable as possible.

Take care, Leslie and Bijou

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Femoral Head Ostectomy (FHO)

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When the neck of the femur is fractured it needs surgical repair. There is a surgical procedure, that was developed many decades ago, that removes the non-functional head, and allows the body to form a false joint. This procedure is called a Femoral Head Ostectomy (FHO). Ostectomy means removal, so the head of the femur, where the ball joint is located, is completely removed.

We also use this procedure when there is a hip dislocation (called a subluxation) and the hip will not stay in the socket, even when we put it back in and put on a special bandage called an Ehmer sling. We also use this surgery for pets with hip dysplasia that will not be undergoing the more extensive hip replacement surgery called a Total Hip.

These are the radiographs of a young German Shepherd that was hit by a car. It was brought to us for a limping problem on the left rear leg. A thorough physical and orthopedic exam revealed some swelling at the left knee. This is a VD (venture-dorsal) view of the pelvis.

Do you see the problem?

The wing of the ileum and the acetabulum are fractured. You can also see that the neck of the femur has been fractured. Compare the problem area above in the red circle to the other side. 

This purple line like gives you a conceptual idea of where the neck of the femur will be cut during the FHO surgery. The exact angle during the procedure is different, and is customized for each bone.

This fracture is 3 week old, and there is swelling and scar tissue around the fracture that is not apparent on this radiograph. Also, this is a large breed dog with large muscles and tendons surrounding the fracture. In a difficult case like this, especially in a young dog that has a long life ahead, we have an orthopedic specialist come to our hospital to perform the surgery. He has special equipment, and over 45 years of experience, to make this a successful surgery with a pain free and active dog that is not limping for the rest of its left.

Before any surgery is performed, our surgeon Dr. Paul Cechner, consults with the owner to go over all of the options. This includes post operative care, which is an important part to make sure adequate healing occurs.

Long before surgery we perform a blood panel and a chest radiograph to make sure there are no other problems from the initial trauma that are not apparent on physical exam. This is important to know before surgery to minimize the risk of anesthesia, and to make sure all problems are corrected. Our patients do not talk to us, and they have high pain thresholds compared to us humanoids, so they don’t always show symptoms and we need to be thorough. We do not want any surprises on the day of surgery.

It is important to take a chest radiograph prior to surgery to make sure the heart and lungs look normal

Once the consultation was performed we put this dog on a pain and anti-inflammatory NSAID called Rimadyl until the day of surgery. Our patient was brought into the hospital the night before surgery and intravenous fluids were started and a pain patch was applied. On the day of surgery another examination was performed by one of our veterinarians to make sure everything is OK. At this point the surgery is a go and our surgeon prepares.

Our patient is anesthetized and the leg is shaved outside of our surgery room

While our patient’s leg is shaved our surgeon starts the scrubbing process with a surgical hand scrub to make sure this is an aseptic procedure

Our patient is brought into surgery, and before anything else is done, is hooked up to our anesthetic monitor and the IV fluid pump (at the top of this picture) is set for the correct amount of fluids to be given during the procedure. These fluids are critical to minimize anesthetic risk. 

Once our patient is stable and under the proper plane of anesthesia, our surgical assistant goes through the multi step process to scrub the leg. This is a crucial step to minimize the risk of infection after the surgery, so we are thorough and methodical in our approach to this part of the procedure. As you view the following pictures you will realize that preparation is a key part of this surgery.

The first step is to tape the leg up in this position

The first scrub of the leg occurs with the leg in this position

He continues scrubbing the leg after our surgeon does an initial draping

Once our surgeon is satisfied with the initial surgical scrub,s he does his own final scrub with a special antiseptic

It is called DuraPrep

It is applied directly over the area of the incision

After the DuraPrep our surgeon drapes the leg with it still hanging. In the background is our anesthetist monitoring anesthesia.

The top of the leg is wrapped in sterile aluminum foil and the tape is cut to bring the leg down

This is the position of the leg during the surgery

The foil is wrapped with a special sterile tape

The appearance of the foot before the final draping

Another drape without a hole is put over the surgical field

Our surgeon makes a custom opening in the drape specific for this surgery

He checks the exact location of where his incision will be before proceeding any further

The next step in the preparation involves and aseptic barrier called Ioban

It is adhered right to the skin where the incision will be

The surgical preparation is now complete and our surgeon is ready to make the skin incision to start the surgery

His sterile bone cutting tool is now opened up

He palpates the landmark for the skin incision 

Let the surgery begin!

Once through the skin the next layer encountered is the subcutaneous (under the skin) layer, sometimes abbreviated as SQ.

The surgical approach goes between several important muscles and tendons in order to gain access to the joint where the fracture is located. These include the biceps femoris muscle, the tensor fascia latae muscle, the superficial gluteal muscle, the deep gluteal muscle, and the vastus lateralis muscle. The muscles and tendons are not cut in order to gain this access to the joint. Careful dissection is performed in this area to preserve the normal anatomy, and not interfere with important nerves and blood vessels  This is one of the most difficult parts of the procedure, and where the experience of our surgeon comes into play.

After much careful dissection Dr. Cechner has the head of the femur exposed in the center of this photo. It is difficult to see because it is covered in scar tissue.  On the left is the special oscillating saw that will cut through the neck of the femur. The opening is small, so our surgical assistant on the right is using a retractor for better visualization

The oscillating saw gives a quick and precise cut with minimal bone trauma

The appearance of the head of the femur just before the cut is complete

A special rongeur is used to smooth off the bone incision

Now the long process of suturing everything back together begins

The postoperative radiograph

Our patient stayed overnight with pain injections administered that were in addition to the pain patch. He went home the next day with antibiotics and oral pain medications The skin sutures were removed in 14 days. After several weeks of confinement, and several weeks of moderate use, he is doing great! Our thanks to Dr. Paul Cechner for doing such a great job.

If you would like to learn much more about how we do surgery at the Long Beach Animal Hospital, including pre-anesthetic testing, anesthesia, and surgical concepts, please visit our Surgical Services web page.

 

 

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Retained Deciduous Teeth

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It is not uncommon for us to encounter dogs with retained baby teeth. If they are still present at 6 months of age when your pet is spayed or neutered, we will remove them.

This dog is 8 months old and has a retained deciduous (D) tooth behind its erupting adult lower right canine (C) tooth. It is interfering with the eruption process of the normal canine tooth and will be removed

The instrument used to remove this tooth is called an elevator. The tooth is gently removed by rotating the elevator around the base of the tooth where it meets the gum line. This is to ensure complete removal of the tooth, including its root. Each tooth takes 5-10 minutes of gentle elevating to remove.

 

When the tooth is removed a small hole remains in the gum. The hole is usually so small that it heals rapidly and rarely requires suturing the gum. The healing time is the same whether the gum is sutured or not.

 

Here is the culprit after removal, notice how deep the root goes. The left 2/3 of this tooth (to the left of the arrow) is the root.

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