Metastatic Bellini Duct Carcinoma: A Case Report and Literature Review.

Collecting duct carcinoma (CDC) of Bellini is a very rare subtype of renal cell carcinoma, generally associated with poor prognosis due to delayed diagnosis and limited sensitivity to conventional therapies used in renal cell carcinoma. We report the case of a 53-year-old female patient who presented with progressive lower back pain and chronic cough. A contrast-enhanced CT urogram revealed a large mass in the left kidney. The patient underwent radical nephrectomy. Histopathological examination confirmed a diagnosis of CDC of the kidney, with positive staining for cytokeratin 7 and epithelial membrane antigen. Staging investigations revealed pulmonary metastatic disease. The patient is receiving first-line chemotherapy with gemcitabine and cisplatin and responded favorably to treatment, showing clinical and radiological stability after three cycles.