Injection site sarcomas in cats

Feline injection-site sarcomas have mostly been associated with the administration of vaccines. Although the pathogenesis remains largely unknown, it is believed that the inflammatory reaction caused from the injection of the compound leads to uncontrolled proliferation of fibroblasts and myofibroblasts that in a subset of cats undergo malignant transformation. Pretreatment evaluation and proper planning of the therapy are essential. Because of the aggressive nature of these tumors, a multimodality treatment approach is being recommended. A combination of surgery and radiation therapy with or without chemotherapy appears to be providing the best prognosis.