Skin and subcutaneous tumors.

In dogs, approximately 25–30% of all neoplasms are reported to arise in the skin. The World Health Organization has a detailed histologic classification scheme for mesenchymal and epithelial skin tumors of domestic animals. All skin and subcutaneous masses should have fine needle aspiration cytology performed as part of the diagnostic process before surgical intervention. Appropriate treatment options in an individual case are based on the tumor type and degree of local tumor disease, the results of staging tests, the presence or absence of metastases, and the overall condition of the patient. Surgery can be used as the sole treatment modality or incombination with chemotherapy, radiation therapy, or other adjunctive treatments. The chapter covers mast cell tumors (MCTs) and soft tissue sarcomas. MCTs are the most common malignant cutaneous tumor in dogs and the second most common cutaneous tumor in cats. The treatment of choice for local cutaneous melanoma in both the cat and dog is surgical excision