Parasitic ovarian dermoid tumor of the omentum-A review of the literature and report of two new cases.

Two cases of a parasitic omental teratoma which originated from an ovarian dermoid that underwent torsion, autoamputation and omental reimplantation are presented. A review of the literature revealed 23 additional cases of omental teratoma which occurred mostly in females. In some cases, the mature teratoma of the omentum showed histological evidence of ovarian stroma, and was associated with a dermoid tumor of the remaining contralateral ovary. It is generally believed that autoamputation and reimplantation of an ovarian dermoid cyst is the most common etiology of omental teratomas. Abdominal pain is the main presenting symptom of these tumors, and on physical examination a mobile abdominal or pelvic mass is often found. Both ultrasonography with colour flow Doppler and CT-scan are helpful in the diagnosis of dermoid tumors, but the correct diagnosis of omental localisation is extremely difficult. Mature omental teratomas may be treated by simple resection. The immature teratomas of the greater omentum, however, are potentially malignant tumors requiring postoperative chemotherapy and radiotherapy.