A rare case of sacral parasitic rachipagus

Background: A sacral parasitic twin is a variant of conjoined twins in which one twin is incomplete.
Case: A female newborn was delivered by cesarean section. Reported inconclusive obstetrical ultrasonography at the first trimester where the pregnancy was initially diagnosed dizygotic and in the second and third trimester was monozygotic. The neonate was born with a mass in the sacrococcygeal region, which was excised 24 days after birth. The mass contained the scalp, skull, cervical spine bone, and brain, which were confirmed as parasitic twins. The post-operative and follow up periods were uneventful.
Conclusion: Sacral parasitic rachipagus is a rare phenomenon; experienced antenatal ultrasonography may assist in the early diagnosis and excision is the treatment.