A case of TFE3 translocation renal cell carcinoma with rare morphological features and literature review.

CONTEXT: TFE3 translocation renal cell carcinoma (RCC) is a rare tumor that represents approximately 1% of RCC. It was classifed as a member of MiT family translocation RCCs by the World Health Organization in 2016. It is characterized by Xp11 translocation gene fusions involving TFE3. The diagnosis of TFE3 translocation RCC is based on immunohistochemical analysis and TFE3 break apart probes in FISH analysis, rather than histological characteristics and imaging examination.

AIMS: To determine the clinico-pathological, immuno-phenotypic, and cytogenetic characteristics of TFE3 translocation RCC.

METHODS AND MATERIALS: The clinical data of a 52-year-old-female patient with TFE3 translocation RCC exhibiting rare morphological characteristics was analyzed, and the tumor tissues were probed using histopathological staining, immunohistochemistry, and fluorescence in situ hybridization (FISH). In addition, the relevant literature was reviewed.

RESULTS

This case is a TFE3 translocation RCC with rare morphological features. It composed of two types of tumor cells. TFE3 and pax-8 were diffusely and strongly expressed in both tumor cells, and they were partially positive for CAIX, RCC, CK, EMA, CD10, Vim, Melan-A, and p504s. Only 2% of the cells were positive for the proliferation marker Ki-67, and the tumor was negative for CK7, CD117, Inhibin-α, HBM45, and p53. FISH showed a positive signal for TFE3 translocation.

CONCLUSIONS

This case was a TFE3 translocation RCC with rare morphological features. Through this case report, we emphasize the importance of in situ detection of TFE3 gene translocation and protein in TFE3 translocation RCC.