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Published on: February 1, 2019
Spontaneous cerebellar primitive neuroectodermal tumor in a juvenile cynomolgus monkey (Macaca fascicularis)
Sydney Mukaratirwa1, Petrina Rogerson, Ana L Blanco
1Charles River, Preclinical Services, Edinburgh, UK. sydney.mukaratirwa@crl.com
Abstract:
A neoplastic mass compressing the left cerebellar hemisphere and hindbrain was observed at trimming in a 3½-year-old male cynomolgus monkey from a control dose group. Microscopically, the neoplastic mass was nonencapsulated, invasive, and showed two morphological patterns. The predominant area consisted of densely packed undifferentiated, polygonal to spindle cells arranged in vague sheets supported by a scant fibrovascular stroma. The other area was less cellular and composed of round neoplastic cells separated by eosinophilic fibrillar material. Immunohistochemical staining for vimentin, synaptophysin, glial fibrillary acidic protein, neuron-specific enolase, neurofilament, and S-100 confirmed the presence of primitive undifferentiated neuroectodermal cells and some cells with neuronal or glial differentiation. On the basis of histopathology and immunohistochemical findings, a diagnosis of cerebellar primitive neuroectodermal tumor with neuronal and glial differentiation was made. Primitive neuroectodermal tumors are rare in animals including nonhuman primates; this is the first published report in this species.
Insights
A rare cerebellar primitive neuroectodermal tumor was diagnosed in a cynomolgus monkey. This finding highlights the importance of monitoring for unusual neoplasms in nonhuman primate research.
Area of Science:
- Veterinary Pathology
- Neuro-oncology
- Nonhuman Primate Research
Background:
- Primitive neuroectodermal tumors (PNETs) are rare central nervous system neoplasms.
- Their occurrence in nonhuman primates is exceptionally uncommon, with limited documented cases.
- Cynomolgus monkeys are vital models in biomedical research, necessitating thorough health monitoring.
Observation:
- A 3.5-year-old male cynomolgus monkey presented with a neoplastic mass compressing the cerebellum and hindbrain.
- Histopathology revealed a non-encapsulated, invasive tumor with two distinct morphological patterns: undifferentiated polygonal/spindle cells and round neoplastic cells.
- Immunohistochemistry confirmed primitive neuroectodermal cells with neuronal and glial differentiation.
Findings:
- Diagnosis of a cerebellar primitive neuroectodermal tumor with neuronal and glial differentiation was established.
- This represents the first reported case of such a tumor in this primate species.
- The tumor exhibited invasive characteristics and complex cellular morphology.
Implications:
- This case expands the known spectrum of spontaneous neoplasms in cynomolgus monkeys.
- It underscores the need for vigilance in detecting and diagnosing rare tumors in research animals.
- Findings contribute to the comparative oncology database, aiding understanding of PNETs across species.
