Papillary renal cell carcinoma with retroperitoneal recurrence and peritoneal dissemination

―A with the report of the cytological findings―

Abstract

Background : Papillary renal cell carcinoma (PRCC) is the second most common type of RCC after clear cell RCC, and is subclassified into types 1 and 2, according to the degree of nuclear atypia. Since RCC cells rarely appear in body cavity fluids, we report the cytological findings in a case of PRCC (type 2) with retroperitoneal recurrence and peritoneal dissemination.

Case : A man in his 50’s who had received maintenance hemodialysis for approximately 8 years was suspected as having a right renal tumor during follow-up. The histologic diagnosis was PRCC (type 2). One month postoperatively, peritoneal dissemination and vertebral metastasis were found. Specimens of the fluid accumulated in the excision cavity were submitted for cytological examination, which revealed clusters of atypical cells in an inflammatory background. The atypical cells contained eosinophilic cytoplasm and irregularly shaped nuclei with prominent nucleoli. The cytological diagnosis was “malignant.” Immunocytochemistry using a cell block revealed positive staining of the atypical cells for CK7, PAX8, but a negative staining result for CK20 and AMACR. Based on these findings, the lesion was diagnosed as a recurrence of PRCC.

Conclusion : When papillary clusters of atypical cells are found in a body cavity fluid, the possibility of PRCC should be included in the differential diagnosis. Diagnostic procedures including immunocytochemistry are recommended.