Are they spherules of ovarian cystic teratoma or daughter cysts of echinococcosis?

Teratoma is a germ cell tumour which accounts for approximately 15-20 % of all ovarian cancers. The tumour is possibly derived from ectodermal differentiation of totipotent cells or mitotic germ cells. We present a case of a 37-year-old female patient with multiple spherical structures floating in a large pelvic-abdominal cystic mass seen on sonographic images. A giant echinococcal cyst gravid with its daughters was the presumed preoperative sonographic diagnosis. The patient underwent excision of the lesion, and the pathological diagnosis was teratoma. The striking feature of multiple spherical structures in the cyst was caused by multiple spherules of a mature ovarian cystic teratoma which were representing numerous mobile sebaceous cysts and desquamative keratin formations.