case_images: PMC5681726_01
case_images: Fine-needle aspirate from a renal mass in a cat. Poorly cellular and hemodiluted sample, with large three-dimensional clusters of moderately pleomorphic epithelial cells with variable nucleus/cytoplasmic ratio, moderate anisokariosis and prominent nucleoli (May-Grunwald-Giemsa stain; Bar=50 mum).
case_images: OpenVetJ-7-294-g001.jpg
case_images: PMC5681726_01_OpenVetJ-7-294-g001.jpg
case_images: F1
case_images: Cytologic samples were markedly hemodiluted, and displayed three-dimensional clusters of moderately pleomorphic epithelial cells with variable nucleus/cytoplasmic ratio, round to oval central nuclei with lacy reticular chromatin and prominent nucleoli (Fig. 1).
case_images: Gross appearance and histopathology of a feline renal mass. (A): Surgically resected kidney. The tumor mass has completely invaded cortex and medulla of the cranial pole; on section, the tumor tissue is non-capsulated and composed of multiple red lobules embedded in a dark red gelatinous tissue (Bar=2.5 cm). (B): Moderately pleomorphic epithelial cells arranged in irregular tubules and papillae, consistent with tubulo-papillary renal cell carcinoma (Hematoxylin and eosin stain; Bar=50 mum).
case_images: OpenVetJ-7-294-g002.jpg
case_images: PMC5681726_01_OpenVetJ-7-294-g002.jpg
case_images: F2
case_images: Grossly, the resected kidney revealed a 4 x 2.5 x 3 cm reddish mass at the cranial pole, non-capsulated, irregularly lobulated, invading both the cortex and the medulla (Fig. 2).
case_images: Immunohistochemistry for erythropoietin (EPO) expression. Diffuse and intense cytoplasmic immunostain for EPO in tumor cells (A: Bar=50 microm) and in tubular cells of non-neoplastic renal tissue adjacent to the carcinoma (B: Bar=100 microm).
case_images: OpenVetJ-7-294-g003.jpg
case_images: PMC5681726_01_OpenVetJ-7-294-g003.jpg
case_images: F3
case_images: In the case here reported, an intense and diffuse cytoplasmic positivity of tumor cells was demonstrated (Fig. 3).