Skin Cancer in Dogs: Understanding Cutaneous Lymphoma

Finding out your dog has one of the rarest types of lymphoma can feel overwhelming. Your vet may provide guidance, but beyond that, you’re often left searching the internet for answers. Luckily, you’ve found this blog! We’re here to help you understand what a cutaneous lymphoma diagnosis means and what steps you can take to help your pup.

What is Cutaneous Canine Lymphoma?

Lymphoma is a cancer of lymphocytes, a type of white blood cell that helps the immune system fight disease.

Most lymphomas develop in the lymph nodes, but cutaneous lymphoma is different—it forms in lymphocytes found in the skin, making it an extranodal lymphoma.

This type of lymphoma is rare, making up only 5% of all canine lymphomas. It typically starts in cells around hair follicles and sweat glands, forming nodules (small red lumps), plaques (flat raised areas), or other skin lesions.

Like other cancers, it can spread to lymph nodes, the bloodstream, and abdominal organs, making early detection important.

Cutaneous lymphoma is usually a T-cell lymphoma, meaning it is often more aggressive and fast-growing. There are two main types:

✔ Epitheliotropic lymphoma – The most common form, affecting skin and mucous membranes.
✔ Non-epitheliotropic lymphoma – Less common but can spread deeper into tissues.

Unfortunately, the exact cause of canine epitheliotropic lymphoma is unknown.

Signs and Symptoms of Cutaneous Lymphoma

Since cutaneous lymphoma affects the skin, the first signs are often visible lesions. Many dogs have a history of chronic dermatitis before diagnosis.

Common symptoms include:
✔ Red, irritated, ulcerated, or infected skin patches
✔ Lumps, plaques, or scabs
✔ Hair loss and excessive itching
✔ Lesions on the gums, lips, nose, or eyelids
✔ Oral discomfort or difficulty eating

As the disease progresses, it may cause systemic symptoms like:
✔ Lethargy
✔ Vomiting or diarrhea
✔ Increased thirst and urination

How is Cutaneous Lymphoma Diagnosed?

If you notice an unusual lump, bump, or lesion, it’s always best to have your vet check it out. Diagnosing cutaneous lymphoma typically involves:

🔬 Punch Biopsy – A small piece of affected skin is removed and examined under a microscope. This is the most reliable way to confirm lymphoma.
💉 Fine Needle Aspirate (FNA) – A small needle is used to collect cells from a lesion or lymph node to look for cancer.
🧬 PCR Testing & Flow Cytometry – These specialized tests help distinguish cancerous lymphocytes from normal immune cells and confirm the diagnosis.

Since cutaneous lymphoma can look like non-cancerous skin conditions, early molecular testing is crucial for an accurate diagnosis.

Treatment Options for Cutaneous Lymphoma

Since this cancer is rare, there isn’t a standard "best" treatment. However, the most common options include:

✔ Chemotherapy – The most widely used treatment. CCNU (lomustine) is often prescribed alone or combined with other drugs.
✔ Surgical Removal – If the cancer is caught early and is in a single location, surgery may help.
✔ Radiation Therapy – Can be effective for localized lymphoma.
✔ Retinoids (Vitamin A Derivatives) – May be used alongside chemo to help slow disease progression.
✔ Prednisone – A steroid that can reduce inflammation and itching.
✔ Doxil (pegylated-liposomal doxorubicin) – Shown to produce temporary remissions.
✔ Mechlorethamine (Mustargen) – A topical chemotherapy that must be applied carefully.

Unfortunately, while many dogs respond well to treatment at first, remission usually lasts only about 3 months.

Because cutaneous lymphoma is aggressive, treatment is often focused on comfort and quality of life rather than a cure.

What is the Prognosis for Cutaneous Lymphoma?

The prognosis for epitheliotropic lymphoma is shorter than other forms of lymphoma. If caught early and treated promptly, most dogs survive between 5-10 months.

However, some dogs experience a slower-growing form of the disease, allowing them to live several years with treatment. There’s no way to predict how each dog will respond.

✔ 50-100% of dogs respond positively to treatment, with noticeable improvement in skin lesions.
✔ Complete remission leads to longer survival times, but lymphoma is not curable, so relapse is common.

Other Types of Lymphoma in Dogs

While cutaneous lymphoma is one of the rarest types, other forms of lymphoma include:

• Alimentary Lymphoma – Affects the digestive system.
• Mediastinal Lymphoma – Develops in the chest area.
• Extra-Nodal Lymphoma – Can appear in organs like the liver or kidneys.
• Multi-Centric Lymphoma – The most common form, affecting multiple lymph nodes.

If your dog has been diagnosed with cutaneous lymphoma, early intervention and the right treatment plan can help maximize their comfort and quality of life.

Most Commonly Affected Dog Breeds

Cutaneous lymphoma, particularly epitheliotropic lymphoma, is more commonly seen in older dogs and tends to affect certain breeds more than others.

While any breed can develop this cancer, the following breeds appear to be at a higher risk:

🐶 Boxers
🐶 Golden Retrievers
🐶 Labrador Retrievers
🐶 Cocker Spaniels
🐶 German Shepherds
🐶 Scottish Terriers
🐶 Bullmastiffs
🐶 Standard Poodles

These breeds may have a genetic predisposition to lymphoma in general, including cutaneous forms. However, age, environmental factors, and overall health also play a role in a dog’s risk.

If you have one of these breeds and notice unusual skin lesions, excessive itching, or hair loss, it’s always best to check with your vet.

References

Lake KM, Rosenkrantz WS, Keating MK. Pathology in Practice. J Am Vet Med Assoc. 2022 May 18;259(S2):1-3. doi: 10.2460/javma.21.04.0190. PMID: 35576181.

Moore PF, Olivry T, Naydan D. Canine cutaneous epitheliotropic lymphoma (mycosis fungoides) is a proliferative disorder of CD8+ T cells. Am J Pathol. 1994 Feb;144(2):421-9. PMID: 7906096; PMCID: PMC1887150.

Pye C. Cutaneous T-cell epitheliotropic lymphoma. Can Vet J. 2023 Mar;64(3):281-284. PMID: 36874549; PMCID: PMC9979720.