Dicephalus Parapagus Dibrachius Dipus Conjoined Twins with Acrania-Exencephaly-Anencephaly Sequence in One Cranial Component: A Case Report

Conjoined twinning is an exceptionally rare complication of monozygotic twinning, and dicephalus parapagus represents one of its rarest lateral fusion patterns. We report a case of dicephalus parapagus dibrachius dipus conjoined twins diagnosed at 14 weeks and 2 days of gestation in a 27-year-old primigravida. Ultrasonography demonstrated two cranial components arising from a single thoracoabdominal body, two upper and two lower extremities, and an apparently single cardiac structure. One cranial component showed findings consistent with the acrania–exencephaly–anencephaly sequence. After multidisciplinary counseling, the patient opted for medical termination. This case highlights the importance of early targeted ultrasonography for defining fusion anatomy and associated lethal anomalies.