Ependymoblastomatous exencephaly: a unique fetal malformation.

Exencephaly/anencephaly is a rare neural tube defect occurring early in embryogenesis. We report a 14-week-old fetus with exencephaly in whom central nervous system tissue was developed and preserved. There were 2 symmetrical structures grossly resembling cerebral hemispheres, which on histologic and ultrastructural study, consisted of a combination of ependymoblastomatous rosettes and canals and primitive neural tissue.