To investigate the clinicopathological features, diagnosis, and differential diagnosis of Xp11.2 translocation/ TFE3 fusion-related renal cell carcinoma.

A total of 15 cases of Xp11.2 translocation/ TFE3 fusion-related renal cell carcinoma were analyzed with regard to clinical data, histology, immunohistochemistry, and fluorescence in situ hybridization (FISH) findings.

Six patients were male and the other nine were female. Their mean age was (31.3±9.3) years. The main clinical manifestations were hematuria and waist pain. Mean tumor diameter was 5.4 cm (range, 1.5-15 cm). Ten cases of the gross specimens were solid and had a grey, yellow, or tan cut surface. Five cases of the gross specimens were cystic-solid. Microscopic examination showed that the distinctive histological pattern was papillary, nested, and acini-like structure. The tumor cells had a clear boundary, eosinophilic or clear cytoplasm, and prominent nucleoli. And in 4 cases, psammoma bodies were observed. Immunohistochemistry results showed that TFE3, PAX-8, and CD10 were diffusely expressed in all cases. The expression of AE1/AE3, vimentin, HMB45, and AMACR/P504S varied among cases. The expression of CAIX, CK7, and CD117 was negative in all cases. All cases showed positive results in the FISH assay.

Xp11.2 translocation/TFE3 gene fusion-associated renal cell carcinoma is a rare renal malignancy and mainly occurs in females. Its diagnosis relies mainly on histopathology, immunohistochemistry, and FISH assay.