[Endocrine tumors of the testis]

The most characteristic endocrine tumours of the testis are germ cell tumours and sex cord/gonadal stromal tumours. They include the primary carcinoid, the relation of which to teratomas is still unclear. In general, gonadal stromal tumours are rare, however, endocrine activity occurs in at least 10%-20%. Among gonadal stromal tumours, only Leydig cell tumours and Sertoli cell tumours are of practical importance. Endocrine disorders are mostly related to Leydig cell tumours (gynaecomastia, pubertas praecox). Although less frequent than the other gonadal stromal tumours, they can, in principle, occur. The large cell calcifying Sertoli cell tumour occurs in association with other complex disorders (i.e. Peutz-Jeghers syndrome). Valuable markers are: inhibin, calretinin, cytokeratin, melan-A, CD-99, Ki-67, androgen receptor and p53. As the conventional morphology and immunohistological markers frequently overlap, unclear cases should be referred to specialised centres.