[Klinefelter's syndrome diagnosed three years after surgery for mediastinal teratoma]. / Diagnostic d'un syndrome de Klinefelter trois ans après chirurgie d'exérèse d'un tératome médiastinal.

INTRODUCTION: The association between some types of tumor and Klinefelter's syndrome (KS) is often missed and diagnosis of the latter delayed, as in this case report. CASE: We present the case of a 20 year-old patient for whom KS was not diagnosed until three years after thoracic surgery for a mediastinal teratoma. DISCUSSION: The association between KS and mediastinal germ-cell tumors is not coincidental; it illustrates the relation between aneuploidy and oncogenesis. In a young adult male, palpation of the scrotum to look for microorchidism is justified when these tumors are diagnosed because 25% occur in patients with KS.