ABSTRACT
Multilocular cystic renal cell carcinoma is a distinct subtype of renal cell carcinoma with its pathological characteristics and good prognosis. Multilocular renal cysts and renal cell carcinoma with cystic change are important differential diagnoses. We report a case of multilocular cystic renal cell carcinoma in a 37-year-old woman who came to the hospital because of the right renal mass. The removed right kidney showed a 6x4 cm well defined cystic mass in the lower pole. On cut section there were multiple cavities in the mass, filled with serosanguineous fluid and focal yellowish solid area. Microscopically, these cysts were lined by a single layer of flat or cuboidal cells consisted of clear cytoplasm with small central nuclei. In some portions of the tumor, the clear neoplastic cells formed sheets within the septa or walls of the cysts.