PRIMITIVE NEUROECTODERMAL TUMOR IN A 2-MONTH-OLD BLACK-AND-WHITE COLOBUS MONKEY

A 2-month-old male black and white Colobus monkey (Colobus guereza kik rryuensis) was euthanatized because of progressive physical deteriorat ion, rear limb paralysis, lymphadenopathy, and the presence of facial and retroperitoneal lumbar masses. At necropsy, soft white masses were present in and around lumbar vertebrae, the subcutis of the face, mul tiple lymph nodes, and the fourth ventricle of the brain. Histologic a nd immunohistochemical analysis of these masses revealed a primitive n eoplasm with both neuronal and glial differentiation, consistent with a primitive neuroectodermal tumor (PNET) with bipotential differentiat ion. The extracranial tumors were synaptophysin (SYN)-positive, glial fibrillary acidic protein (GFAP)-negative, and neurofilament protein ( NFP)-negative, while the intracranial tumor was SYN-positive, GFAP-pos itive, and NFP negative.