A case study of metastatic Xp11.2 translocation renal cell carcinoma effectively treated with sunitinib.

We report a case of Xp11.2 translocation renal cell carcinoma (RCC) whose lung metastases were effectively treated with sunitinib. A 43-year-old woman presenting with upper abdominal pain was diagnosed with a left renal tumor. Laparoscopic left radical nephrectomy was performed. Histopathological examination of the surgical specimen revealed a clear-cell carcinoma of the left kidney. Two years later, multiple lung metastases were detected and the patient was treated daily with 50 mg sunitinib. A computed tomography scan performed after 2 cycles of sunitinib treatment revealed partial regression of these metastases. The partial regression has been maintained for >3 years. In retrospective evaluation of the primary RCC, tumor cells showed strong nuclear staining for transcription factor E3 (TFE3) protein and TFE3 split-fluorescence in-situ hybridization revealed translocation involving the TFE3 gene. These findings strongly support diagnosis of Xp11.2 translocation RCC.