Massive intracranial immature teratoma. Report of a case with polyhidramnios and intense pelvic pain.

A case of massive intracranial immature teratoma in a female stillborn is reported. She was the product of the second pregnancy of a 25-year-old healthy woman. The pregnancy was unremarkable until the 25th week of gestation when the mother noticed a rapid enlargement of her abdomen and intense pelvic pain. Because of the pain, a cesarean section was indicated, and a stillborn weighing 2750g with macrocephaly was delivered. The cranial contents weighed 1350g and showed a huge tumoral mass with only a rim of normal brain. A histologic diagnosis of immature teratoma was made. Massive intracranial teratomas are rare tumors and their occurrence in intrauterine life is even rarer. Their histogenesis is unknown, and there is no explanation for their continuous growth during embryogenesis. A prenatal diagnosis of this rare condition can be made by ultrasound, computed tomography, or magnetic resonance imaging.