Multilocular cystic renal cell carcinoma: a rare, unique entity and diagnostic challenge.

Multilocular cystic renal cell carcinoma (MCRCC) is a rare tumor with an excellent prognosis. We report a case of MCRCC in a 33-year-old male who presented with vague discomfort in the right flank for the last 1.5 years. Computed tomography (CT) scan revealed a multiseptate cystic mass in the upper pole of the right kidney. Surgically resected well-circumscribed cystic mass was formed entirely by thin-walled non-communicating cysts of variable size separated from surrounding renal parenchyma by a distinct fibrous wall. On histopathological examination, clear cells with prominent cytoplasmic border and low nucleocytoplasmic ratio were present in the lining epithelium as well as in the intervening septa. No solid area was appreciated in the cystic mass. Finally, after corroboration with the imprint cytology findings, the tumor was diagnosed as MCRCC with TNM staging and Fuhrman nuclear grading of T1bN0M0 and grade 1, respectively.