[Early puberty and thoracic mass: presentation of a case].

A case is reported of a 7 year old patient with progressive dyspnea and genital development according to Marshall and Tanner criteria at the G2 VP3 stage. A mass of regular and well-defined borders was found in the chest, with calcifications and cystic areas of heterogeneous content. Basal measurements of FSH, LH and testosterone were <10 mIU/mL, 12.2 mIU/mL and 724 ng/dL, respectively. α-fetoprotein was 145.1 ng/mL. Excising the tumor improved respiratory symptoms, diminished hormone levels and stopped the process of precocious puberty. Pathology of the mediastinal tumor corresponded to a germ cell tumor with a predominant component of mature teratoma and choriocarcinoma. Neoplastic causes of precocious puberty are uncommon; its diagnosis is essential in order to provide timely treatment.