A giant placental mass masquerading as an acardiac twin

Abstract

Background

Chorangioma is a benign vascular tumour of the placenta. Majority of tumours are small and incidental. Large chorangiomas (colloquially “giant chorangiomas”) are relatively uncommon. Case report: A primiparous woman, booked at an external institution, presented at 32 + 2 weeks of gestation with abdominal pain. Ultrasound scan showed a thick placenta and features worrisome for fetal anemia. The patient underwent emergency caesarean section in view of non-reassuring fetal status. At delivery, there was a large mass adherent to the placenta, raising the clinical possibility of an acardiac twin. Histopathological examination showed a singleton placenta and a multinodular proliferation of capillaries with nucleated erythrocytes, which established the diagnosis of a giant chorangioma with evidence of fetal anemia. Baseline investigations of the neonate showed anemia and thrombocytopenia, complicated by cardiomegaly and hepatomegaly. Conclusion: Although histologically benign, large chorangiomas may be associated with adverse clinical outcomes for the fetus. Given their large size, they may clinically masquerade as acardius amorphous, especially if antenatal history or follow up is limited or absent.