Eosinophil granulocytic sarcoma in a New Zealand white rabbit.

An 18-month-old New Zealand White rabbit developed a rapidly growing firm perianal mass. Within 2 months, the mass increased in size from 4.0 x 2.0 cm to 7.5 x 7.0 x 3.5 cm. Cut surfaces of the mass were white to yellow with foci of hemorrhage. Histopathologic examination revealed neoplastic granulocytes that invaded the dermis of the overlying skin, subcutaneous tissue, and the regional skeletal muscle. The tumor was comprised of myeloid cells with large eosinophilic cytoplasmic granules that had the histochemical and ultrastructural features of eosinophils. This is the first report of an eosinophil granulocytic sarcoma in lagomorphs.