Mediastinal germ cell tumour associated with Klinefelter syndrome. A report of case and review of the literature.

A 14-year-old boy with Klinefelter syndrome (KS) and a large mediastinal tumour is presented. Human chorionic gonadotropin and oestradiol were markedly increased. An attempt at radical resection was performed. Histological examination revealed a malignant germ cell tumour of mixed histologic pattern composed of choriocarcinoma and components of mature teratoma. Four courses of cisplatin, bleomycin, and etoposide were given. The patient is without any evidence of tumour recurrence 20 months after diagnosis. A review of the literature revealed another 40 cases of primary mediastinal germ cell tumour (PMGCT) associated with KS. Compiled data from larger series demonstrate that at least 8% of male patients with PMGCT have KS, 50 times the expected frequency. In contrast to PMGCT in patients without KS, all tumours were of nonseminomatous histology, and the average age was considerably lower, Tumours in prepubertal boys were associated with precocious puberty.