Renal Cell Carcinomas: Report of Two New Cases and Review of the Literature Confirming Nearly Universal Multilocular Cystic Morphology.

We report two novel cases of Xp11 translocation renal cell carcinomas with the gene fusion in adult females aged 40 and 74 years. Both cases were extensively cystic and contained only minimal clear cells lining cysts and within septal walls, raising the differential diagnosis of multilocular cystic renal neoplasm of low malignant potential. By immunohistochemistry, both neoplasms labeled for PAX8, TFE3, cathepsin K and Melan A but not for HMB45. On review of the published literature and the two cases reported herein, over 90% of renal cell carcinomas (RCCs) have been described as cystic. The correlation of the fusion with extensively cystic morphology represents the strongest association of fusion partner with clinicopathological features among -rearranged RCC reported to date.