# Case report: Renal adenoma in a captive ocelot (Leopardus pardalis) in Costa Rica

## TL;DR

A 12-year-old captive ocelot in Costa Rica was diagnosed with a rare kidney tumor called a renal adenoma, the first detailed case in this species.

## Contribution

This is the first detailed microscopic and immunohistochemical report of a renal adenoma in a captive ocelot.

## Key findings

- The tumor occupied 25% of the right kidney and showed well-differentiated epithelial tubular neoplasia.
- Vimentin and Pax-8 were the only positive immunohistochemical markers.
- The tumor was diagnosed as a renal adenoma, a rare condition in neotropical wildcats.

## Abstract

Reports of renal neoplasia are rare in neotropical wildcats. Ocelots (Leopardus pardalis) are medium-sized wildcats living in America’s tropical forests. A 12-year-old captive ocelot was diagnosed with a renal mass occupying approximately 25% of the total right kidney volume. The tissue was stained with routine hematoxylin and eosin (H&E) and periodic acid–Schiff (PAS). Immunohistochemistry with the following markers was performed: cytokeratin (CK) AE1/AE3, CK19, CK 7, CD10, vimentin, Melan A, HMB45, Pax-8, and Wilms’ tumor 1 (WT1). Histopathology revealed a well-differentiated epithelial tubular neoplasia with less than one mitotic figure per 2.37mm2 field. Vimentin and Pax-8 were the only positive markers. Immunohistochemically, neoplasia was diagnosed as a renal adenoma. Renal adenomas are seldom reported in neotropical wildcats. Reports on wild species are valuable for properly establishing a clinical prognosis for captive species. To the best of our knowledge, this is the first report that provides detailed microscopic and immunohistochemical descriptions of renal adenoma in a captive ocelot.