Renal Cell Carcinoma with t(X;17)(p11.2;q25) in a 5-year-old Taiwanese Boy. A Case Report and Review of the Literature

Abstract

The classification of adult renal cell carcinomas (RCCs) is well established and is mainly based on histopathologic features and genetic abnormalities [1]. In comparison, pediatric RCCs are more difficult to classify. In the past few years, it has become evident that a great majority of pediatric RCCs belong to the newly-recognized family of Xp11 translocation RCCs [2, 3]. These tumors are genetically characterized by different chromosome translocations, resulting in gene fusions between Xp11.2 and TFE3 transcription factor genes [2]. At least 5 genetic variants have been identified, including t(X;1)(p11.2;q21) translocation with PRCC-TFE3 fusion [4], t(X;1)(p11.2; p34) translocation with PSF-TFE3 fusion [5], inv(X)(p11; q12) translocation with NonO (p54)-TFE3 fusion [5], t (X;17)(p11.2;q25) translocation with ASPL-TFE3 fusion [6],and t(X;17)(p11.2;q23) with CLTC-TFE3 fusion [7]. Additionally, a subset of epithelioid RCCs that harbor t (6:11)(p11.2;q12), which fuses the Alpha gene and TFEB transcription factor gene, has been described [8]. A novel translocation of t(X,3)(p11;q23) has recently been reported in a 32-year-old female patient [9]. As TFEB and TFE3 are closely-related members of the microphthamia transcription factor (MiTF) family (a subfamily of basic helix-loop-helix leucine zipper transcription factors), it has been proposed that these tumors are classified as “MiTF/TFE translocation carcinomas” [2]. In the English literature, most case reports and series studies originate from Western countries [3, 6, 9–14], and case reports and series studies of pediatric RCCs in Asia are rare [15, 16]. Recently, Chen et al described a molecularlydocumented Xp11.2 translocated RCC in a 6-year-old Taiwanese boy [17]. Herein, we report a case of an Xp11.2 translocated RCC in a 5-year-old Taiwanese boy. The diagnosis was established based on the histopathologic features, nuclear expression of TFE3 protein, and the presence of the type 1 TFE3-ASPL fusion gene as detected by reverse transcriptase-polymerase chain reaction. A literature review of translocation RCCs is also included.