Collecting Duct Carcinoma (Bellini Duct Carcinoma) Presented as a Renal Cyst

ABSTRACT

Renal cysts are frequently seen in the general population. Most small simple renal cysts are managed by conservative treatment. A renal cell carcinoma (RCC) presenting as a renal cyst is extremely uncommon, and collecting duct carcinoma is a rare type of RCC. This report describes a collecting duct carcinoma initially presnted as a renal cyst. The patient was a 52-year-old man who had been diagnosed with a renal cyst in the left lower pole 8 years earlier but was not regularly follow-up. He presented with left flank pain and gross hematuria. Computed tomography revealed a heterogeneous enhanced mass in the left lower pole and multiple para-aortic lymph nodes. He underwent radical nephrectomy and lymph nodes dissection which confirmed collecting duct carcinoma with sarcomatoid differentiation.