Pseudo-precocious puberty associated with mediastinal teratoma and polycystic ovary.

A 10-month-old girl with sexual precocity of recent onset was found to have elevated levels of estrogens, progesterone and androgen precursors, associated with a polycystic left ovary. After ovariectomy, estrogen and androgen levels were normal, and the clinical symptoms began to regress. A few months later, a huge mediastinal mass was unexpectedly discovered. Removal of the mass, identified later as a benign teratoma, was followed by the total normalization of the clinical and hormonal findings. The patient's pseudo-precocious puberty might have been due to an ovarian overproduction of estroprogestins and androgens, associated with a paraneoplastic production of progesterone, or in theory, it might have been due to a gonadotropin-like stimulation of the ovary by the teratoma.