Atypical postcesarean epithelioid trophoblastic lesion with cyst formation: a case report and literature review.

We report an extremely rare case of atypical postcesarean epithelioid trophoblastic lesion with cyst formation. A 41-year-old Chinese woman presented with lower abdominal pain and menstrual disorder. Her serum human chorionic gonadotropin (hCG) was low (0.373 IU/L), and her urine hCG was negative. Ultrasound images showed a 3.7×2.8×2.5 cm(3) mass on the surface of the lower uterine segment, and a laparoscopy indicated a cystic mass in the serosal surface of the lower uterine segment. Histology indicated a cystic lesion consisting of epithelioid trophoblastic cells with an intermediate pattern between a classical placental site nodule and an epithelioid trophoblastic tumor; thus, the term atypical postcesarean epithelioid trophoblastic lesion with cyst formation was appropriate. As in atypical placental site nodule, serum hCG monitoring after treatment is necessary.