Giant intracranial teratoma and lack of cortical development in a fetus. Case report.

Antenatal diagnosis of an intracranial neoplasm is extremely rare. The authors describe a case in which a 21-week-old fetus was found, by using fetal ultrasonography, to have a large intracranial mass. Fetal magnetic resonance (MR) images, obtained at 21 and 25 weeks' gestation, supported the diagnosis of a teratoma. As the tumor increased in size, near-complete brain atrophy ensued. Premature labor was induced, and a nonviable fetus died within minutes of delivery. Postmortem analysis confirmed a teratoma occupying a major portion of the intracranial space. In cases in which abnormal brain development is suspected in a fetus, the use of fetal MR imaging can give a clearer picture of the pathological entity, which may allow for a more accurate diagnosis. The usefulness of fetal MR imaging in monitoring brain development and tumor growth during treatment planning is discussed.