[Leydig-cell tumors of the testicle]

Leydig's cells tumor account for 1-2% of all testicular tumors. The authors report a rare case of benign Leydig's cells tumor in a young man with gynecomastia. They examine the embryogenesis, the hormonal modifications, the criteria of malignancy, the treatment and results. They present a review of the literature pertaining to this rare tumors.