[Renal carcinoma associated with MiTF/TFE translocation: report of six cases in young adults]

The authors present six cases of renal carcinoma associated with MiTF/TFE translocation in young adults. This tumour is one of the newly identified entities of the WHO 2004 classification.

Six patients with MiTF/TFE translocation were identified in a series of 636 adults operated between 2001 and 2005. The diagnosis was based on cytogenetic analysis and immunohistochemistry (IHC) in three patients and IHC alone in the other three patients.

Four women and two men between the ages of 28 and 42 years presented a tumour with a mean diameter of 6 cm (range: 3-15 cm). The TNM classification of these tumours was pT1N0 (n=2), pT2N0 (n=1), pT3aN+M0 (n=1), and pT3aN+M+ (n=2). The mean follow-up was 32 months. One M+ patient died six months after the operation, another two pT3 patients developed metastatic disease and pT1 or pT2 patients were alive without recurrence. The histological features comprised a typical papillary architecture with large eosinophil and/or clear cells. IHC showed TFE3 (n=5) or TFEB (n=1) expression. Cytogenetic analysis demonstrated a t(X;1)(p11.2;p34) or t(X;17)(p11.2;q25) translocation in two patients expressing TFE3 and a t(6;11)(p21; q13) translocation in the patient expressing TFEB.

Renal carcinoma associated with MiTF/TFE translocation can be diagnosed by IHC. However, cytogenetic analysis on fresh or frozen material allows characterization of the translocation and should be performed on all renal tumours in young adults. Prognosis is related to stage. In the future, the diagnosis of more cases of this type of carcinoma will allow more precise definition of the clinicopathological profile and the most appropriate management.