A supernumerary ovary of the omentum with cystic change: report of two cases and review of the literature.

A supernumerary ovary is a rare gynecological anomaly. Particularly rare is the presence of cystic changes within the supernumerary ovary. We report two cases of neonates found to have a supernumerary ovary resembling an omental cyst. To the best of our knowledge, this report describes the first antenatal diagnosis of an omental cyst with a supernumerary ovary. To explain this unusual occurrence, it is suggested that an omental cyst becomes detached from the ovarian tissue and implants itself in the greater omentum, and that these supernumerary ovaries are of true embryologic origin, and not due to post-surgical or post-inflammatory implantation.