Renal Cell Carcinoma Associated with Xp11.2 Translocation:Clinicopathologic and Immunohistochemical Findings of 4 Cases

Abstract

Background : The new WHO classification includes the recently described renal cell carcinomas (RCC) that are associated with several different translocations, involving chromosome Xp11.2, and they all result in gene fusions involving the TFE3 gene. The authors describe the clinicopathologic and immunohistochemical findings of 4 patients who had the morphologic features of RCC with Xp11.2 translocations. Methods : Among 9 surgically resected and pathologically proven pediatric RCCs, 4 showed a typical RCC histopathology with the Xp11.2 translocation. Immunohistochemical stains were performed for TFE3, AE1/AE3, epithelial membrane antigen, vimentin, HMB45, S-100 protein and CD10. Results : The 4 study subjects included one male and 3 females, and their chief complaints were gross hematuria and abdominal pain. Histologically, the tumors showed two different histologic types: type 1 tumors (2 cases) that corresponded to those of ASPL-TFE3 RCC, and type 2 tumors (2 cases) that corresponded to PRCC-TFE3 RCC. Nuclear TFE3 immunostaining was seen in 3 cases. All the tumors were immunoreactive for CD10, and vimentin and cytokeratin were expressed in 3 cases and HMB-45 was expressed in 2 cases. Conclusions : Our results show that significant numbers of pediatric RCC are translocation-related. Therefore, when one encounters an RCC in the pediatric population, the possibility of a translocation-related RCC should be kept in mind.