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Spontaneous pericardial mesothelioma in a rhesus monkey
1Pathology Toxicology Consultants, Paramus, NJ 07652, USA.
Abstract:
Spontaneous tumors in nonhuman primates are of great importance. A spontaneous pericardial mesothelioma was observed in an 18-year-old female rhesus monkey. Grossly, the visceral pericardium was multifocally irregular and thickened with tan discoloration and was soft in consistency. Histologically, the pericardium contained highly in-folded branching fronds lined by a single layer of cuboidal cells. Tumor invaded into approximately half of the thickness of the atrial and ventricular muscles. Tumor penetration was not observed into the atrial or ventricular cavity. Within the myocardium, neoplastic cells formed glandular structures which were lined by cuboidal to columnar cells. Neoplastic cells were weakly positive with PAS and strongly positive for colloid iron and alcian blue. Immunohistochemically, neoplastic cells were positive for both vimentin and cytokeratin and negative with CEA and Leu-M1, indicating mesothelial origin. To the best of the authors' knowledge, this is the first report of a spontaneous pericardial mesothelioma in a rhesus monkey.
Insights
This study reports the first case of spontaneous pericardial mesothelioma in a rhesus monkey. This rare tumor originated from the mesothelium and invaded the heart muscle.
Area of Science:
- Veterinary Pathology
- Primate Oncology
Background:
- Spontaneous tumors in nonhuman primates are crucial for comparative oncology research.
- Understanding primate tumorigenesis aids in human disease modeling.
Observation:
- An 18-year-old female rhesus monkey presented with a spontaneous pericardial mesothelioma.
- Gross examination revealed thickened, irregular visceral pericardium.
- Histopathology showed branching fronds lined by cuboidal cells, invading atrial and ventricular muscles.
Findings:
- Neoplastic cells formed glandular structures within the myocardium.
- Tumor cells were positive for vimentin, cytokeratin, colloid iron, and alcian blue.
- Immunohistochemistry confirmed mesothelial origin, with negativity for CEA and Leu-M1.
Implications:
- This case represents the first documented instance of pericardial mesothelioma in a rhesus monkey.
- Highlights the importance of nonhuman primates in studying rare tumor types.
- Provides valuable data for comparative pathology and oncology research.