[Leydig cell tumor presenting as precocious pseudopuberty in a 4-year-old boy].

Objectives: To report one case of isosexual precocious pseudopuberty in a 4-year-old boy caused by an interstitial cell testicular tumor.
Methods: Physical exam, blood tests, hormonal determinations, adrenal suppression tests, bone age, orchiectomy and pathologic study of the specimen were performed.
Results: Physical examination showed a boy with muscle development, acne; body, sexual and face hair corresponding to an older boy; with increased volume of the left testicle and infantile contralateral testicle. Urinary 17-ketosteroids were elevated and did not decrease after dexametasone. Bone age corresponded to an 11-year-old standard. Pathologic study showed an interstitial cell tumor. Puberty changes disappeared after orchiectomy.
Conclusions: This diagnosis should be taken into consideration in every case of accelerated sexual development in a boy with testicular tumor and without maturation of the contralateral testicle.