Histopathologic and Immunohistochemistry Findings in Feline Renal Cell Carcinoma

Abstract

The biological behavior and immunohistochemical features of feline renal cell carcinoma (RCC) have not been well characterized. In the present study, immunohistochemical examinations were performed in 12 feline cases of RCC. The RCC consisted of solid ( n = 2), solid-tubular ( n = 2), tubular ( n = 3), papillary ( n = 2), tubulopapillary ( n = 2), and sarcomatoid ( n = 1) type lesions. Of the cases with RCC, 1 developed metastatic disease and 6 cases had no evidence of recurrence at 80 to 2292 days after surgery. One papillary-type tumor had cuboidal cells with scant cytoplasm and monomorphic nuclei, and the other had pseudostratified columnar cells with abundant cytoplasm. Immunohistochemistry revealed that the tumor cells in most cases were positive for cytokeratin (CK)7, CK20, KIT, and CD10, with the exception of cases of the solid type with clear cytoplasm (solid anaplastic), papillary type with columnar cells, and sarcomatoid types. A small number of tumor cells in the solid anaplastic and in the sarcomatoid types were positive for aquaporin-1. Increased expression of N-cadherin and Twist along with nuclear accumulation of β-catenin were observed in the sarcomatoid type. These results indicated that CK, KIT, and CD10 are relatively strongly expressed in most feline RCC. The solid anaplastic RCC exhibited CD10 expression with the absence of distal tubule marker expression. Although immunohistochemistry profiles were relatively consistent with those described in human RCC, the histopathologic features were different from those seen in humans. Epithelial-mesenchymal transition (EMT) marker expression in the current cases may suggest the involvement of an EMT-like mechanism in the development of sarcomatoid RCC in cats.

Feline sarcomatoid renal cell carcinoma with peritoneal carcinomatosis and effusion

“…22 Our case of feline SRCC is similarly invasive with near effacement of the left kidney, areas of necrosis, and extension beyond the renal capsule. Although peritoneal metastasis has been reported in feline SRCC, 3,17 significant peritoneal effusion, as we observed, has not been described previously.…”

“…The reported cases of feline SRCC indicate little or no pancytokeratin expression, with consistently strong vimentin expression. 10,17 In our case, neoplastic cells in the renal mass had rare, strong, cytoplasmic immunoreactivity for pancytokeratin and diffuse, strong, cytoplasmic vimentin immunoreactivity (Table 1; Suppl. Fig.…”

“…23 Of these, only CD10 has been reported in feline SRCC, but was not commercially available as a validated feline IHC during manuscript preparation. 17 Cytoplasmic SMA immunoreactivity has also been reported in one case of feline SRCC. 17 In our case, immunolabeling with PAX8, CK18, and SMA in the primary tumor was strong (Table 1).…”

“…17 Cytoplasmic SMA immunoreactivity has also been reported in one case of feline SRCC. 17 In our case, immunolabeling with PAX8, CK18, and SMA in the primary tumor was strong (Table 1). The histologic morphology, combined with the IHC staining pattern and postmortem findings, was compatible with the final diagnosis of feline SRCC.…”

“…SRCCs are particularly rare tumors in cats, with only 3 previous reports. 3,10,17 Much of the information on this neoplasm has been extrapolated from human literature. SRCC in people is also rare, accounting for only 8% of human RCCs.…”