Primitive neuroectodermal tumor in a two-month-old black and white Colobus monkey

Area of Science:

• Veterinary Pathology
• Comparative Oncology
• Primatology

Background:

• Primitive neuroectodermal tumors (PNETs) are rare, aggressive neoplasms originating from primitive neural cells.
• Understanding PNETs in non-human primates is crucial for comparative oncology and conservation medicine.
• Colobus monkeys (Colobus guereza kikuyuensis) are Old World monkeys facing conservation challenges.

Observation:

• A 2-month-old male Colobus monkey presented with progressive physical deterioration, hind limb paralysis, lymphadenopathy, and facial/retroperitoneal masses.
• Necropsy revealed soft, white masses in the lumbar vertebrae, facial subcutis, lymph nodes, and the brain's fourth ventricle.
• Tumors exhibited histological and immunohistochemical features of a primitive neoplasm with neuronal and glial differentiation.

Findings:

• The neoplasm was identified as a primitive neuroectodermal tumor (PNET) with bipotential differentiation.
• Extracranial tumors were positive for synaptophysin (SYN) and negative for glial fibrillary acidic protein (GFAP) and neurofilament protein (NFP).
• The intracranial tumor was positive for SYN and GFAP, but negative for NFP, indicating distinct differentiation patterns.

Implications:

• This case highlights the potential for PNETs in Colobus monkeys, contributing to the understanding of neoplastic diseases in non-human primates.
• The bipotential differentiation observed has implications for PNET classification and understanding tumor behavior in comparative settings.
• Findings can inform diagnostic approaches and potential therapeutic strategies for similar neoplasms in veterinary and conservation contexts.