Translocation Carcinomas of the Kidney Pedram Argani, MD a, * , Marc Ladanyi, MD b a Department of Surgical Pathology, The Johns Hopkins Hospital, Weinberg Building, Room 2242, 401 North Broadway, Baltimore, MD 21231-2410, USA b Department of Pathology, Room S-801, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA A subset of renal carcinomas that most commonly affect young patients has been characterized by various translocations that involve chromosome Xp11.2; all result in gene fusions that involve the TFE3 transcription factor gene. In the past few years, several different Xp11.2-translocation carcinomas have been identified and characterized at the morphologic and molecular levels. These include a distinctive renal carcinoma that bears a translocation with the identical breakpoints and identical resulting ASPL–TFE3 gene fusion as alveolar soft part sarcoma (ASPS), a rare pediatric soft tissue neoplasm of uncertain histogenesis. These Xp11.2 translocation carcinomas are now accepted as a distinctive entity in the 2004 World Health Organization’s renal tumor classification [1]. In addition, a novel and unusual epithelioid renal neoplasm that is characterized by a recurrent t(6:11)(p11.2;q12) chromosome translocation has been described, and recently was found to bear a fusion that involves the related TFEB transcription factor gene. Because TFEB and TFE3 are members of the MiTF/TFE family of transcription factors, and the Xp11 and t(6;11) translocation neoplasms share clinical morphologic, immuno- histochemical, and molecular features, we propose to expand the existing category of Xp11-translocation carcinomas and group these neoplasms under a new category of ‘‘MiTF/TFE family translocation carcinomas.’’ This article describes the morphologic and molecular features of these recently-defined neoplastic entities. This work was supported in part by NIH RO1 CA95785 (to ML). * Corresponding author. E-mail address: pargani@jhmi.edu (P. Argani). 0272-2712/05/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.cll.2005.01.008 labmed.theclinics.com Clin Lab Med 25 (2005) 363–378