Cystic nephroma: a histologic and immunohistochemical study of 10 cases.

Context: Cystic nephroma is a rare and controversial benign multicystic renal tumor. While the clinical, radiologic, and histologic features of cystic nephroma are well described, the immunohistochemical features are not. The role of immunohistochemistry in the differential diagnosis, which includes multicystic renal cell carcinoma, is also unknown.