What is Melanoma in Cats?

What is Melanoma in Cats?

What is it?

Melanoma in cats is a type of cancer arising from melanocytes, which produce pigment. It can occur in various body parts, including the skin, mouth, and eyes. Melanomas can be either benign or malignant and are more commonly found in older cats.

How is it Treated?

Treatment for melanoma in cats typically involves surgical removal of the tumor. Depending on the location and extent of the cancer, additional treatments such as radiation therapy or chemotherapy may also be recommended. In some cases, immunotherapy may boost the cat’s immune system to fight cancer.

Breed Predispositions

There are no known breeds that are predisposed to melanoma in cats. However, age, gender, and immune status may increase the risk of developing melanoma.


Nina had always been an attentive cat owner, keeping a watchful eye on her beloved feline friend, Misty. But when she noticed a dark, pigmented mass on Misty’s ear, she couldn’t help but feel a sense of unease. Deciding to err on the side of caution, Nina took Misty to the veterinarian for a thorough examination. To Nina’s dismay, the veterinarian diagnosed Misty with melanoma, a form of skin cancer that can affect both humans and animals. Overwhelmed by the diagnosis, Nina knew she had to learn more about melanoma in cats in order to provide the best care possible for Misty.

Melanoma is a type of skin cancer that affects animals. It is one of the most common cancers in cats. It accounts for up to 40% of feline skin cancer cases. Cats are particularly susceptible to this disease because they have thick fur coats that trap sunlight and act as a shield against UV rays.

Cats are at risk for melanoma because they spend most of their day outside in the sun. The sun’s ultraviolet (UV) light causes melanin cells to produce an extra pigment called pheomelanin. Pheomelanin protects the cat’s skin from burning, but it turns into malignant melanoma when too much of it builds up over time.

Benign melanocytic neoplasms are common in cats. Melanomas are made up of pigmented cells. Malignant melanomas are rarer. Unlike humans, cats do not have freckles. Instead, they have dark spots on their bodies caused by melanin deposits.

Cat melanomas are usually located on the head, eyes, and ears. Other locations include the nose, eyelid, lip, genital area, anal region, and perineum (the area around the anus). Most melanomas in cats are diagnosed when the patient is less than two years old. However, some cats develop melanomas later in life.

Malignant melanomas are more likely to affect younger cats. Older cats are more likely to develop benign melanocytic neoplasm. Tufts University says malignant melanoma accounts for less than one percent of feline oral tumors.

Types of Melanoma in Cats

Oral melanomas are the most commonly seen type of melanoma in cats and are often found during routine dental examinations. They tend to occur in older cats and are associated with sun exposure.

There are three main types of oral melanoma in cats:

  1. Spindle cell melanoma – This variant accounts for about 80% of oral melanomas in cats. These tumors typically arise in the mucosa of the hard palate or tongue and are characterized by elongated cells arranged in bundles.
  2. Epithelioid melanocytic neoplasm – This variant represents about 15% of oral melanomas. These tumors comprise epithelioid cells that resemble those seen in human skin lesions.
  3. Lymphomatoid melanotic schwannoma – About 5% of oral melanomas are lymphomatoid melanotic Schwannomas. These tumors are rare variants of cutaneous melanomas that contain nests of malignant B cells.
Types of Melanoma in Cats

The location of origin and degree of maturity impact the prognosis for oral melanomas. Surgical excision, radiation therapy, chemo, and immunotherapy are all options for treatment.

Causes of Skin Cancer in Cats

Melanoma is a type of cancer that is caused by changes in the skin cells. Cats can be at risk for developing melanoma due to genetics, UV exposure, and certain viruses.

Genetics can play a role in cat melanoma development; certain breeds, like Siamese and Burmese cats, have an increased risk. The affected areas are often facial, oral, ear canal or paw pad regions.

UV radiation from sun exposure increases the chances of developing melanoma in cats. Excessive sun exposure can cause cell mutations and DNA damage, leading to cancerous growth in the skin.

Viral infections such as feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) contribute to the oncogenic transformation of cells, thus increasing the cat’s risk for tumor formation and melanomas.

Other causes may include exposure to toxic chemicals and environmental pollutants, becoming topical products applied directly to the skin. These toxins can mutate healthy cells into malignant cells if present over long periods becoming carcinogenic.

These factors all increase a cat’s risk for developing melanoma, so it’s essential for pet owners to pay attention to any abnormal changes on their pet’s skin and contact their veterinarian immediately, as early detection is critical for successful treatment and prognosis.

Symptoms of Skin Cancer in Cats

Because these cancers are slow-growing, many owners never notice them until they become large enough to cause pain or discomfort. For example, cats with skin cancer often experience itching, bleeding, ulcers, sores, crusting, swelling, hair loss, weight loss, vomiting, diarrhea, fever, lethargy, depression, seizures, coma, blindness, paralysis, breathing difficulties, difficulty swallowing, coughing, sneezing, excessive drooling, open wounds, and bloody discharge.

If left untreated, these cancers can metastasize to internal organs, including the lungs, liver, heart, bones, brain, eyes, kidneys, bladder, pancreas, spleen, stomach, intestines, lymph nodes, thyroid gland, salivary glands, adrenal glands, prostate, penis, testicles, ovaries, uterus, vagina, mammary glands, and nipples.

Diagnosing Malignant Melanoma in Cats

Vets use several methods to detect cat melanomas, including physical examination, biopsy, cytology (sample cells), and imaging tests.

  • A physical exam includes checking the cat’s skin and fur for abnormalities and looking at its eyes, ears, mouth, nose, throat, genitals, paws, tail, and anus. Vets may also perform blood work, ultrasound exams, X-rays, and CT scans.
  • Vets may recommend a biopsy if no obvious sign of a problem exists. This involves taking a small tissue sample from the affected area(s) and sending it to a lab for analysis. The vet uses this information to determine whether the tumor is benign or malignant.
  • Cytology is another method used to diagnose melanoma in cats. Cytology samples cells from the affected area. These cells are examined under a microscope and analyzed for signs of cancerous growth.
  • Imaging tests include ultrasonography, nuclear scintigraphy, and computed tomography. Ultrasound is often used to examine internal organs, including the kidneys, bladder, liver, spleen, pancreas, heart, lungs, lymph nodes, thyroid gland, ovaries, uterus, testicles, and adrenal glands.
  • Nuclear scintigraphy is similar to ultrasounds except that radioactive material is injected into the cat’s bloodstream instead of sound waves. In addition, nuclear scintigraphy allows vets to view tumors inside the body.
  • Computed tomography (CT) scans create cross-sectional images of the body. They’re usually done after a patient receives intravenous contrast dye. Contrast dye highlights areas where blood flow is abnormal.

After determining whether a tumor is benign or malign, vets treat the condition accordingly. Benign tumors grow slowly and rarely spread to other parts of the body. Malignant tumors are aggressive and can metastasize (spread to other parts of the cat’s body).

Benign tumors can be surgically removed, frozen, burned off, or seared. Malignant tumors require surgery, chemotherapy, radiation therapy, immunotherapy, or combinations. Cats diagnosed with melanoma should receive regular examinations and monitoring until the disease is controlled.

Treatment Options for Cats with Melanoma

Vets treat melanoma in cats like any other type of cancer. They use chemotherapy drugs, radiation therapy, surgery, and immunotherapy.

Treatment Options for Cats with Melanoma

Chemotherapy Drugs

Cats with melanoma often need chemotherapy drugs to treat cancerous tumors. The most common treatment option is vinblastine (VBL) and dacarbazine (DTIC). VBL is administered intravenously every three weeks, while DTIC is given orally once per week. Both treatments work well for many cats, but some may experience side effects.

Side effects include vomiting, diarrhea, hair loss, weight gain, weakness, fever, fatigue, depression, and seizures. In addition, some cats develop kidney problems after receiving these drugs.

Ask your veterinarian about alternative therapies if you are considering treating your cat with chemotherapy. These include immunotherapy, surgery, radiation, photodynamic, and laser therapy.

Radiation Therapy

Cats with melanomas often need radiation therapy to treat cancerous tumors. Radiation therapy uses x-rays to kill cancer cells. The goal is to shrink the tumor enough to remove it surgically.

There are two types of radiation therapy: external beam radiation (EBR) and internal radiation (brachytherapy). EBR involves placing radioactive material directly outside of the body. Brachytherapy involves inserting small pellets containing radioactive materials inside the cat’s body.

External beam radiation works well when there’s only one large tumor. However, brachytherapy is usually preferred because it allows doctors to target multiple tumors simultaneously.

Brachytherapy is typically performed after surgery to reduce the risk of recurrence. In addition, external beam radiation is usually done before surgery.

Both treatments are effective, but each has its advantages and disadvantages.


Surgery often removes tumors, but this doesn’t work well when the cancer is deep within the cat’s body.

If the tumor is small and close to the skin surface, the vet may recommend a simple surgical procedure called a shave biopsy. This involves removing only a tiny sample of tissue from the tumor site.

The vet may suggest a complete surgical excision if the tumor isn’t near the skin. The entire tumor and some healthy surrounding tissue are removed during this procedure.

After the surgery, the cat must be monitored closely for signs of infection or bleeding. Cats who undergo surgery usually recover quickly and return home within a week.


Immunotherapy is another option, but it only works on certain cancers. For example, cats with melanoma often respond well to immunotherapy treatments. Immunotherapy is a treatment that uses the body’s immune system to fight cancer cells.

Immunotherapy stimulates the cat’s immune system to recognize and destroy cancerous cells. This process is called tumor vaccination.

Two types of immunotherapy are used to treat cats with melanoma: passive and active therapy. Passive treatment involves giving the cat a vaccine made from dead cancer cells. Active treatment consists in injecting the cat with live cancer cells.

Passive therapy is usually given once every three months until the cat stops responding to the vaccine. After that, active treatment is typically given once per week for four weeks.

Both therapies work well for most cats with melanoma. However, some cats may not be able to tolerate the side effects of either therapy. Therefore, it’s important to discuss treatment options with your veterinarian.

How to Prevent Feline Melanoma?

Melanomas are cancers that develop in animals’ skin cells. They are most common in dogs but can also occur in cats.

Cats get melanomas more often than dogs but account for less than 1% of all canine cancers.

There are several things you can do to prevent melanoma in your cat.

  • Prevent Sun Exposure

Sun exposure is one of the biggest causes of melanoma in cats. If you live in areas where sunlight is intense, make sure to keep your cat indoors,

  • Check Your Cat’s for Skin mass Care Needs

Checking up on your cat’s skin care needs is another thing you should do to prevent melanoma.

Ensure your cat gets regular veterinary exams, especially if they spend lots of time outdoors.

Ask your vet about changes in your cat’s behavior or appearance, such as excessive licking, scratching, hair loss, or unusual eating habits.

  • Make Sure Your Cat Has Access to Shade

Shading your cat from direct sunlight helps protect him from ultraviolet radiation, which may cause skin damage and accelerate the growth of tumors.

Keep your cat indoors whenever possible, so he doesn’t need to spend time outside.

  • Provide Appropriate Nutrition

Providing your cat with appropriate nutrition is essential to his health.

A diet rich in antioxidants can help fight off free radicals, which may lead to cancerous cell formation.

Avoid feeding your cat foods containing artificial colors and flavors. These additives can irritate your cat’s digestive tract and increase the likelihood of developing cancer.

  • Monitor Your Cat’s Body Condition

Monitoring your cat’s body condition is another way to ensure your pet stays safe from cancer.

Look for signs of being overweight, including excessive belly size, loose skin around the neck, shoulders, hips, and legs, and fatty deposits under the chin.

Watch out for sudden weight gain or loss, which could indicate illness.

Frequently Asked Questions

Melanoma in cats usually appears as a mole or brown patch on the skin. It may be velvety to the touch and gradually grow more significant over time. If left untreated, melanoma can spread to other parts of the body. There is no known cure for melanoma in cats, but treatment typically includes surgery to remove the cancerous tissue and chemotherapy or radiation therapy as needed.

Cancerous lumps on cats are either hard or soft tissues. The hardness depends on the cat’s skin type and the lump’s size. For example, a large chunk could be problematic if it is located on a wide area of the cat’s body, such as its neck, chest, back, paws, or tail. On the other hand, smaller lumps could be soft because they are located on thinner areas like the belly, head, ears, legs, or bottom.

A fatty tumor looks like a white mass on a cat’s body. It usually appears under the skin near the tail base. The mass is soft and rubbery when touched.

A fatty tumor is a benign growth that occurs most often on cats’ tails. They are common tumors in older cats. Fatty tumors are caused by a buildup of fat cells in the tissues around the tail base. Most fatty tumors do not cause any problems. However, some cats develop a painful lump at the bottom of their tail. This condition is called feline fibrosarcoma.

Fatty tumors are sometimes mistaken for another type of cancer, such as lymphoma (cancer of the lymph nodes). You should immediately take your cat to the veterinarian if your cat develops a fatty tumor.

Yes, it is painful. Melanosis is a condition with excessive skin pigmentation caused by increased melanin production. It is usually seen in dark-skinned people. In cats, it is called Iris Melanosis (IM). IM occurs when the iris becomes darker than usual due to hyperpigmentation. This causes the cat’s eyes to appear black. The coloration is permanent and cannot be removed.

Iris melanoma is a type of cancer that affects the iris. It is most commonly found in cats and other animals, such as dogs and horses. Iris melanoma typically develops from a lesion (abscess) on the surface of the iris or within its tissues.

Skin cancer in cats is not usually itchy. However, itching may occur if the tumor is large or has spread to other parts of the cat’s body. If you notice your cat scratching excessively and have concerns about skin cancer, schedule an appointment with a veterinarian for a diagnosis and possible treatment.

Mammary tumors in cats generally are benign, and most will not require treatment. However, if a mammary tumor is causing discomfort or has started to spread, it may be necessary to remove it.

Melanoma in cats can look like a mole or dark patch on the skin. It is usually painless but can occasionally be sore. If it grows, it may become hard to see and cause discomfort.

The early stage of melanoma in felines is when the lesion is a light brown or black spot. The lesion may grow slowly and not be noticeable to the naked eye. As melanoma spreads, it may become darker in color, accompanied by signs of aggression or Appetite loss. The lesion can grow larger if left untreated and invade more profoundly into the skin. 

Some substances that have been found to shrink tumors in cats are as follows: heat, radiation therapy, chemotherapy, and immune system-stimulating drugs. For example, one study found that cats treated with radiation therapy had a greater than 50% decrease in tumor size, as opposed to only 10-15% for those who received chemotherapy.

The most common cause of tumors in cats’ mouths is squamous cell carcinoma, a type of skin cancer. Other causes include lymphoma (a form of cancer that originates from lymphocytes), leukemia (a type of cancer that develops from cells in the blood), and adenocarcinomas (cancerous tumors composed chiefly of glandular tissue).

Cats can typically survive skin cancer for about six months, but the length of time a cat stays depends on many factors, including how aggressively the cancer is treated. Surgery may be the best option if your cat has a tumor that is only pea-sized or smaller. If the cancer is larger, chemotherapy and radiation therapy may be necessary.

Cancer typically progresses by growing and spreading from the original site. Cancer cells can spread to other body parts through the bloodstream, lymphatic system, and skin. Cancer cells can also grow in organs such as the liver or brain. Cancer near a significant blood vessel may make it difficult to grow and spread. However, this does not mean that cancer cannot metastasize from these areas.

A veterinarian typically diagnoses DIFFUSE Iris Melanoma after examining the eye to reveal changes in the color or size of the iris. DIFFUSE Iris melanoma usually does not spread from the eye. However, because tumors can occur anywhere in the body, checking all potential exposure areas is essential. IMMEDIATE Iris melanoma should be treated as soon as possible because the tumor may grow rapidly and cause vision loss or other serious health problems. Surgery, radiation therapy, and chemotherapy are the most common treatments for diffuse iris melanoma.

The veterinarian may surgically remove the tumor and any surrounding tissue. If the tumor is located near a major organ, such as the lungs or heart, surgery may be necessary to remove it completely.

Unfortunately, there is currently no vaccine available for feline melanoma. However, research is ongoing to develop a vaccine, and treatments may be available in the future. Other possible treatments include surgery to remove the tumor, radiation therapy, and chemotherapy.

There is no accurate answer to this question, as the cost of melanoma treatment can vary dramatically from one clinic to another and even from one type of melanoma treatment to another. However, on average, it would likely cost around $10,000 – $15,000 per cat for a complete course of conventional chemotherapy and radiation therapy.

Disclaimer: The information provided on this veterinary website is intended for general educational purposes only and should not be considered as a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a licensed veterinarian for any concerns or questions regarding the health and well-being of your pet. This website does not claim to cover every possible situation or provide exhaustive knowledge on the subjects presented. The owners and contributors of this website are not responsible for any harm or loss that may result from the use or misuse of the information provided herein.

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