A novel case of t(X;1)(p11.2;p34) in a renal cell carcinoma with TFE3 rearrangement and favorable outcome in a 57-year-old patient.

Renal cell carcinoma (RCC) with translocation involving Xp11.2 (Xp11.2-RCC) is a rare neoplasm that usually occurs in children and young adults. This incidence is underestimated in adults because its morphological similarities with clear-cell RCC or papillary RCC2,3, as well as immunohistochemical and cytogenetic analyses are not carried out systematically in adults. We present a novel case of Xp11.2-RCC in a 57-year-old woman. The histologic features were those of a clear-cell RCC. Molecular cytogenetic analysis showed an uncommon t(X;1)(p11.2;p34) with TFE3 rearrangement and no alteration of chromosome 3. The immunohistochemical analysis showed expression of the TFE3 protein. Only nine cases of (X;1)(p11.2;p34) have been published, most of them occurring in children or young adults. To our knowledge, this is the second report of such a translocation in a patient older than 55 years. After a follow-up period of 13 months, the patient showed no evidence of disease. The clinical outcome was favorable, indicating that this particular translocation might be associated with a good prognosis. This observation confirms that Xp11.2-RCC are very likely to be underestimated in adults older than 40 years, and it highlights the importance of performing immunohistochemical and cytogenetic analyses in RCC for accurate diagnosis. Copyright (c) 2010 Elsevier Inc. All rights reserved.