Melanocytic Tumors of the Skin and Digits in Cats
Melanocytic tumors are benign or cancerous growths, arising from melanocytes (pigment-producing skin cells) and melanoblasts (melanin-producing cells that develop or mature into melanocytes). These tumors do not seem to have a genetic basis; however, cat ages 8 to 14 seem to have a predilection to the condition.
In addition, melanocytic tumors can be found in both dogs and cats. If you would like to learn more about this condition affects dogs, please visit this page in the PetMD health library.
Symptoms and Types
Melanocytic tumors may develop anywhere on a cat's body, though it is more common on the head, toes (digits), ear, and nose. Depending on the location of the lesion, they may be pigmented or non-pigmented. Additionally, lymph nodes near the affected area may become enlarged.
These masses may develop slowly or rapidly, but in advance stages of the disease, the cat may have trouble breathing or make harsh lung sounds due to the spread of the cancer into the lungs. Furthermore, if the masses have spread to a limb, the cat may appear lame or have difficulty walking.
The cause of melanocytic tumors in cats is currently unknown.
Cell examination and special stains may distinguish amelanotic melanoma from poorly differentiated mast cell tumors, lymphoma, and carcinoma. Your veterinarian may also X-ray the affected area to determine if the underlying bone has been compromised, especially if the growth is one a toe (or digit).