The ovarian dysgenesis of trisomy 18.

Ovarian abnormalities have been reported as a rare feature of the trisomy 18 syndrome. Gross and histological examination of autopsy material from 13 female infants with this syndrome revealed that ovarian dysgenesis, in varying degrees of severity, is more common than is indicated by the literature. The characteristic changes are reduction in germ cells due to necrobiosis, and the presence of mesothelial clefts and abnormal masses of stromal cells.