Volume 10, Number 2Case ReviewLeydig Cell Hyperplasia Revealed by GynecomastiaCase ReviewMohamed Jamal El FassiMoulay Hassan FarihMohamed Fadl TaziSoufiane MellasLeydig cell tumors are rare and represent 1% to 3% of all tumors of the testis. Leydig cell tumors affect males at any age, but there are 2 peak periods of incidence: between 5 and 10 years and between 25 and 35 years. Their main clinical presentation is a testicular mass associated with endocrinal manifestations that are variable according to age and appearance of the tumor. Our patient, a 17-year-old adolescent, presented with an isolated and painless hypertrophy of the right mammary gland. Clinical examination found gynecomastia and no testicular mass. Hormonal levels and tumor markers were normal. Testicular sonography showed an ovular and homogeneous right intratesticular mass 6 mm in diameter. We treated the patient with an inguinal right orchidectomy. The anatomopathological study found a nodule of Leydig cell hyperplasia. The patient recovered without recurrence at 8-month follow-up. The patient opted for mammoplasty 2 months after his orchidectomy rather than wait for the spontaneous gradual regression of his gynecomastia, which requires at least 1 year. Leydig cell hyperplasia manifests in the adult by signs of hypogonadism, most frequently gynecomastia. Although many teams prefer total orchidectomy because of the diagnostic difficulty associated with malignant forms, simple subcapsular orchidectomy should become the first-line treatment, provided it be subsequently followed by close surveillance, as it preserves maximum fertility, and these tumors usually resolve favorably. [Rev Urol. 2008:10(2):164-167]FertilityTesticular tumorLeydig cell hyperplasiaNonseminomatous germ celltumorsGynecomastia