[Leydig cell tumours of the testis. Two cases presenting opposing sexual features : gynaecomastia, precocious virilisation, and revealed by study in vitro of aromatisation activity].

Two Leydig cell tumours presented with changes in sexual characteristics. The first patient was a child with precocious puberty whilst the second was that of an adult with recurrent gynaecomastia. Histochemical examination in vitro of tumour tissue from the second patient made it possible to explain the synthesis of oestrogens by a primary tissue destined to an essentially androgenic activity.