Intraventricular fetus in fetu: report of one case.

Fetus in fetu is a very unusual intracranial mass in infancy, with only a few cases noted in the literature. Our discovery of a two-month-old girl will be another case for this kind of condition. Dissection and radiologic study of the fetus showed an axial skeleton and long bones, corresponding to the generally recognized diagnostic criteria for fetus in fetu. Previously reported cases are briefly reviewed and the differences between teratoma and fetus in fetu are discussed.