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

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.

Keywords: adenoma; neoplasia; ocelot; renal; wildlife.

Figure 1

(A) Macroscopic appearance of the renal adenoma in the right kidney. The cross-section shows a large beige multilobulated mass occupying one of the renal poles. (B) Microphotography of renal adenoma. Tumor tissue grows in a diffuse confluent tubular pattern with the presence of eosinophilic intraluminal proteinaceous material H&E stain 200×. (C) Magnification of B, scattered tumor-associated lymphocytic infiltration H&E stain 400×. (D) Intraluminal PAS-positive material PAS stain 400×. (E) Tubular tumor tissue, the majority of the neoplastic cells have moderate to strong cytoplasmic immunoreactivity for vimentin immunohistochemistry staining 400×. (F) Strong to moderate immunoreactivity for Pax-8 staining shows the interface between normal renal tissue and neoplasia. Pax-8 immunohistochemistry staining 40×.