Melanomas in Dogs and Cats
📝 Summary
Melanomas are pigmented tumors of dogs and cats that may be benign or malignant, favoring the mouth, eyes, rectum, and perineum. Wide surgical removal is used, but malignant melanosarcomas spread readily and carry a poor prognosis.
1 Symptoms
Benign melanomas arise either under the epidermis or in the dermis. The former starts as a pigmented patch that becomes a firm small nodule; the latter is smooth, hairless, raised, well-defined, and pigmented.
Malignant melanomas are larger, brown-black to gray, and if they ulcerate can invade nearby tissue. Lumps occur alone or in clusters, black to gray-black and nodular, oozing ink-like fluid when cut. Malignant change, called melanosarcoma, grows fast, adheres to surrounding tissue, ulcerates, and spreads to the lungs, liver, spleen, and lymph nodes, causing anemia and wasting.
2 Causes and Transmission
Melanomas are not contagious. They arise from pigment-producing cells and are seen more in dark-coated breeds such as Cocker Spaniels, Boston Terriers, and Scottish Terriers.
Mucosal melanomas of the mouth, eyes, rectum, and perineum behave more aggressively than skin forms, though the exact trigger is unknown.
3 Diagnosis
A veterinarian examines the lump and takes a biopsy; special stains may be needed when pigment is absent and the tumor is hard to identify.
Imaging of local lymph nodes and chest helps check for spread, which is common with malignant forms.
4 Treatment
Wide surgical removal of the melanoma is the main treatment. Benign tumors have a good outcome, while malignant melanomas have a poor prognosis and may need follow-up anti-cancer medication.
Protecting the healing site from licking supports recovery after surgery.
5 Prevention
There is no certain prevention, but regular skin and oral exams help find pigmented lumps early, when removal is most successful.
Any new or changing dark lump, especially in the mouth or on mucosal surfaces, should be checked promptly because malignant forms progress quickly.
Still Have Questions About Melanomas in Dogs and Cats?
Explore more disease articles or ask our expert team for professional advice
Go to Q&A →