Diagnosis and treatment of renal cell carcinoma accompanying the cystic lesion

Approximately 15% of cases of renal cell carcinoma (RCC) present cystic configuration on radiologic and pathologic examination. The mechanisms of cyst formation in RCC are intrinsic multilocular cystic growth (multiloculated renal cell carcinoma: MCRCC), unilocular cystic growth (cystadenocarcinoma), cystic necrosis and tumor growth from the epithelial lining of a preexisting cyst. These cystic lesions accompanying RCC are often difficult to differentiate from the multiloculated renal cyst (MLC) or other benign cystic lesions such as hemorrhagic cyst and so on. Differential diagnosis of the complicated renal cystic lesions is discussed in this review.