Xp11.2 translocation renal cell carcinoma with SFPQ/PSF-TFE3 fusion gene: A case report with unusual histopathologic findings

Xp11.2 translocation renal cell carcinoma (Xp11tRCC) is a subtype of renal cell carcinoma (RCC) characterized by chromosomal rearrangement of the region harboring the transcription factor for immunoglobulin heavy-chain enhancer 3 (TFE3). Xp11tRCCs comprises 20% to 40% of RCCs of children and adolescents and is generally associated with good prognosis. However in adult, the incidence of this tumor is relatively low (1% to 4%), suggesting a more aggressive course. TFE3 gene is fused by translocation to numerous partner genes, and definitive molecular characteristics can be difficult to verify. In this case report, we presented a case of Xp11tRCC with the SFPQ/PSF-TFE3 chimeric gene. The fusion gene was detected by 5'-rapid amplification of cDNA ends (5'RACE). The tumor was found to be in an advanced stage with multiple lymph node metastases. The histological characteristics of the tumor were different from those of XP11tRCC with other more frequently detected fusion genes.