Complete hydatidiform mole with coexisting fetus: A case report.

Complete hydatidiform mole with coexisting fetus (CHMCF) is an exceptionally rare and clinically challenging obstetric condition. Its diagnosis and management require a high index of suspicion and a multidisciplinary approach. This report presents the case of a woman in her 30s who presented for a routine prenatal examination at 15 weeks of gestation. Ultrasonography revealed a placenta with a mixed echogenicity area exhibiting a characteristic honeycomb-like appearance, alongside a coexisting viable fetus with normal biometry. Serum β-human chorionic gonadotropin (β-hCG) was markedly elevated at 259,762 mIU/mL. Through serial monitoring and multidisciplinary consultation, a diagnosis of CHMCF was suspected and later confirmed by postnatal genetic analysis. The pregnancy was complicated by persistent vaginal bleeding at 21 weeks, leading to termination following a comprehensive risk-benefit assessment. This case underscores the diagnostic challenges, the critical role of cytogenetic analysis, the importance of patient counseling regarding the significantly elevated risks of obstetric complications and gestational trophoblastic neoplasia (GTN), and the necessity for meticulous post-evacuation surveillance. This report aims to enhance clinical awareness and outline a structured management protocol for this rare entity.