Collecting duct carcinoma of the kidney: A case report.

Collecting duct carcinoma (CDC) is a rare type of renal tumor, arising from the distal collecting ducts. The prognosis of this disease is extremely poor due to its rapid progression with widespread metastases. The present study reported a case of CDC involving the right renal region of a 62-year-old female patient, presented with right-flank pain that had persisted for one month. A computed tomography scan demonstrated multiple hypoattenuating quasicircular lesions, 0.5-4.3 cm in size, in the upper pole of the right kidney. Following the diagnosis of a right renal tumor, laparoscopic radical resection of the right kidney was performed. Pathological examination demonstrated that the tumor cells were arranged in a glandular or papillary pattern, and marked cytological atypia was observed. Immunohistochemical staining revealed that the tumor cells were positive for epithelial membrane antigen and cytokeratin (CK)7, while they reacted focally with vimentin. However, the tumor cells were negative for CK20, CD10, uroplakin III and p63. Based on these findings, the patient was diagnosed with CDC. In conclusion, immunohistochemical analysis is critical in establishing an accurate diagnosis of CDC and distinguishing this tumor from other subtypes of RCC.