Periocular cutaneous mast cell tumors in cats: evaluation of surgical excision (33 cases).

Objective: To describe feline periocular cutaneous mast cell tumor (CMCT) clinical features, rates of local tumor recurrence and metastases, and cat survival time following surgical excision.

Animals Studied: Thirty-three cats with periocular CMCTs.

Procedures: Medical records of cats diagnosed with periocular CMCTs were reviewed; cats were included if CMCTs were surgically excised and the diagnosis confirmed by histopathology. The appearance, size, location and histopathology findings of CMCTs were recorded. Rates of local recurrence, metastasis, and survival time following surgical excision were collected when available.

Results: All periocular CMCTs were restricted to the eyelids. In addition to surgical excision, three cats were treated with adjunctive therapy (strontium-90 irradiation or cryotherapy) intraoperatively. Local tumor control was achieved in 22/23 cats with a minimum follow-up of 30 days (median follow-up time of 711 days); one cat developed disseminated CMCTs but no local recurrence. Cats with periocular CMCTs had a median survival time of 945 days. Metastatic disease involving peripheral lymph nodes or abdominal viscera was not detected in any cat at any time during the study. All periocular CMCTs were classified as low-grade based on histopathology, and complete excision was achieved in approximately 50% of cases.

Conclusions: Surgical excision of periocular CMCTs in cats is an effective treatment option with rare local recurrence and metastases, even following incomplete surgical excision.