Cutaneous lymphoma is a rare but clinically significant form of malignant lymphoproliferative disease in small animals. It can be primary (arising in the skin) or secondary (metastasis from systemic lymphoma).

In dogs

Types of cutaneous lymphoma:

• Epithelial T-cell lymphoma is the most common form.
• Non-epithelioid lymphoma is less common, usually B-cell (more aggressive).

Symptoms:

• Initially, redness, itching, peeling, similar to allergic or autoimmune dermatitis.
• Then - ulcers, nodules, papules, alopecia, hyperpigmentation.
• The oral cavity, skin around the anus, and eyelids may be affected.

Diagnosis:

• Skin biopsy with histology is the main method.
• Immunohistochemistry (CD3 for T cells, CD79a for B cells).
• Blood tests, ultrasound, X-rays - to assess the systemic process.

Treatment:

• Chemotherapy: lomustine, prednisone, CHOP protocol.
• Local therapy: corticosteroids, topical agents, radiation therapy.
• Prognosis: cautious. Median survival is 6-12 months, depending on the response to therapy.

In cats

Cutaneous lymphoma in cats is less common than in dogs, but often has an aggressive course.

Types:

• Mostly B-cell (aggressive), but a T-cell form is also possible.
• It can be primary or metastatic.

Clinical signs:

• One or more nodules, plaques, ulcers on the skin, sometimes on the face, ears, and limbs.
• It can be accompanied by loss of appetite, weight loss, and depression.

Diagnosis:

• Biopsy with histology.
• Immunohistochemical examination (to determine the phenotype).
• Testing for FeLV/FIV.

Treatment:

• Chemotherapy: (vincristine, doxorubicin, cyclophosphamide, lomustine).
• Palliative treatment: prednisolone.

The prognosis is unfavorable, especially in case of systemic involvement.