Hyperferritinemia revealing renal carcinoma with TFE3 gene translocation: a rare case report.

We present the case of a 39-year-old man who was hospitalized due to hyperferritinemia. During the etiological workup, an abdominal-pelvic MRI incidentally revealed a left renal cystic mass classified as Bosniak III. A partial left nephrectomy was performed. Histologically, we observed malignant tumor proliferation with a polymorphic architecture. Immunohistochemistry revealed that the tumor cells weakly expressed keratins (AE1/AE3), but not carbonic anhydrase IX. Due to these unusual findings and the patient's young age, fluorescence in situ hybridization (FISH) was performed, revealing a rearrangement of the TFE3 gene in over 80 % of the tumor cells.