UC Davis

A 3-year-old, 4.0 kg, female, spayed Silver Marten cross rabbit (Oryctolagus cuniculus) was presented for evaluation of a suspected recurring spindle cell sarcoma following primary excision by the referring veterinarian. Physical examination revealed a large subcutaneous mass on the left metatarsus and a fine needle aspirate revealed suspected neoplastic spindle cells. Hematologic evaluation was unremarkable and a computed tomography scan revealed invasion of the mass into skeletal muscles but showed no evidence of metastatic disease. An amputation was performed, after which the patient recovered uneventfully. However, the rabbit was found suddenly dead at time of discharge from unknown cause. Gross, histologic, and immunohistochemical evaluation was performed, which diagnosed a peripheral nerve sheath tumor. To the authors’ knowledge, this is the first detailed case report of a lagomorph peripheral nerve sheath tumor specifically confirmed with immunohistochemistry. Wide surgical excision is considered the treatment of choice and may be combined with radiation therapy. Further research is required to determine risk factors, the role of adjunctive therapy, as well as long-term prognoses for peripheral nerve sheath tumors in rabbits.