TFE-Altered Renal Cell Carcinoma: A Contemporary Review With Practical Insights and Diagnostic Pearls for Surgical Pathologists.

Since the initial recognition of unique renal cell carcinomas (RCC) with the ASPCR1::TFE3 gene fusion, the category of MiT-family RCC has evolved to include TFE3 -rearranged RCC, TFEB -rearranged RCC, and TFEB -amplified RCC, 3 entities with significant intracategory and intercategory variation in morphology and clinical behavior. Given their ability to mimic one another as well as more common RCC subtypes, we present a review here that summarizes relevant morphologic, immunohistochemical, and molecular findings as well as a practical approach to diagnosis. Accurate diagnosis of TFE-altered RCCs is critical to provide patients and treating clinicians with pertinent prognostic information and inform treatment decisions in the event of advanced disease.