Ovarian complete hydatidiform mole: case study with molecular analysis and review of the literature.

Ectopic complete molar pregnancy in the ovary is an exceptionally rare event. Here we present a case of ovarian complete hydatidiform mole in a 20-year-old gravida 2 para 1 woman. At presentation, the patient underwent excision of a hemorrhagic left ovarian cyst, with routine sections demonstrating a hemorrhagic corpus luteum with a single microscopic focus of detached atypical trophoblast, without chorionic villi. Subsequent left salpingo-oophorectomy for persistently elevated human chorionic gonadotropin led to a final diagnosis of complete hydatidiform mole arising in the ovary. The fallopian tube was unremarkable. Zygosity was determined using short tandem repeat analysis, confirming the diagnosis of monospermic complete mole. In the clinical setting of a markedly elevated human chorionic gonadotropin level and an ovarian mass, histopathologic examination is critical in distinguishing ectopic pregnancy from choriocarcinoma. Short tandem repeat analysis can be a useful adjunct to histologic diagnosis in challenging cases.