Placental site trophoblastic tumor in the ovary of a young child with isosexual precocious puberty.

The authors report a unique case of a primary ovarian placental site trophoblastic tumor (PSTT) in a 30-month-old girl who presented with isosexual precocious puberty of 1 month duration. Laboratory studies revealed mildly elevated beta human chorionic gonadotropin (37.5 mIU/ml; reference range <3.0 mIU/ml) and estradiol (74 pg/ml; reference range 0 to 56 pg/ml) serum levels. A 3.5-cm right ovarian mass was detected radiographically. The tumor was confined to the ovary as proven by the preoperative staging workup and the exploratory laparotomy. Microscopically, it was composed of intermediate trophoblastic cells with angioinvasive growth and deposition of fibrinoid material. The tumor cells were diffusely positive for human leukocyte antigen G, melanoma cell adhesion molecule (CD146), and cytokeratins (AE1/AE3, CK18, and CAM 5.2). Stains for human chorionic gonadotropin, alpha-inhibin, and human placental lactogen showed focal immunoreactivity. Serum markers returned to normal postoperatively. The patient remains disease-free at 24-months follow-up. We propose that tumors morphologically identical to uterine PSTT may rarely occur as gonadal germ cell tumors in children.