JPC SYSTEMIC PATHOLOGY
URINARY SYSTEM
December 2023
U-M23 (NP)
Signalment (JPC # 870468-10): Rhesus monkey
HISTORY: Incidental histopathologic finding.
HISTOPATHOLOGIC DESCRIPTION: Kidney: Multifocally lining the collecting ducts of the inner medulla, there are several multinucleate cells, up to 4 per HPF, with up to 20 nuclei which are morphologically similar to nuclei within adjacent normal epithelial cells. These cells have a moderate amount of vacuolated eosinophilic cytoplasm, and frequently bulge into the tubular lumen. Papillary ducts are lined by stratified cuboidal epithelium and multifocally contain fewer previously-described multinucleated epithelial cells.
MORPHOLOGIC DIAGNOSIS: Kidney, medulla, collecting tubule and papillary duct epithelium: Multinucleated epithelial cells, multifocal, few, rhesus macaque (Macaca mulatta), nonhuman primate.
CAUSE: Incidental finding
GENERAL DISCUSSION:
- There is a single report of multinucleated epithelial cells in renal collecting tubules
of wild-caught rhesus and cynomolgus macaques; these findings had not been described before and, presumably, are a normal variation in macaques.
- Multinucleated epithelial cells are not associated with degenerative, inflammatory,
hyperplastic or neoplastic changes; there is no evidence of clinical disease, urine abnormalities, or other histologic lesions.
PATHOGENESIS:
- Unknown
TYPICAL CLINICAL FINDINGS:
- None
TYPICAL GROSS FINDINGS:
- None
TYPICAL LIGHT MICROSCOPIC FINDINGS:
- Multinucleated epithelial cells in the collecting tubules in the lower medulla (from the mid-medulla to the tip of the renal papilla)
· Up to 2-20 nuclei per cell; nuclei are morphologically similar to normal epithelial cells
- Epithelium lining the ducts of Bellini is stratified (part of collecting duct just proximal to location where duct empties in the area cribosa, normally composed of simple columnar epithelium)
ADDITIONAL DIAGNOSTIC TESTS:
- None
DIFFERENTIAL DIAGNOSIS:
- Granulomatous inflammation
- Morbilliviral syncytial cells
COMPARATIVE PATHOLOGY:
· Humans: Multinucleated epithelial cells lining the proximal convoluted tubules have been attributed to degenerative changes in association with renal sclerosis
- A report of a case of mushroom poisoning in humans describes multinucleated tubular epithelial cells; interruption of cytokinesis of cell division due to the mycetial toxin is the proposed pathogenesis
REFERENCES:
1. Chamanza R, Naylor SW, Carreira V, et al. Normal Anatomy, Histology, and Spontaneous Pathology of the Kidney, and Selected Renal Biomarker Reference Ranges in the Cynomolgus Monkey. Toxicol Pathol. 2019;47(5):612-633.
2. Harman MB, Hogan JM. Multinucleated epithelial cells in the tubules of the human kidney. Arch Pathol.1949;47:29.
3. O’Donnell M, Fleming S. The renal pathology of mushroom poisoning. Histopathology. 1997;30:280-282.
4. Seaman WJ. Multinucleated epithelial cells of renal collecting tubules in macaques. Vet Pathol. 1986;23:87-88.
