Supplementary Material for: Intraplacental Choriocarcinoma in Twin Pregnancy Causing Fetomaternal Haemorrhage and Single Twin Demise: Case Report

Gestational choriocarcinoma is a rare aggressive form of gestational trophoblastic neoplasia. In cases of intraplacental choriocarcinoma the tumour is confined to the placenta. Intraplacental choriocarcinoma in twin pregnancies is a very rare occurrence with less than five previously reported cases in the literature. In this case a 34-year-old primiparous woman, pregnant with dichorionic diamniotic (DCDA) twins, underwent an emergency caesarean section for fetal distress at 35 weeks gestation after presenting in preterm labour. Twin A was delivered with no signs of life. The demise was attributed to fetomaternal haemorrhage (FMH) secondary to intraplacental choriocarcinoma. The mother’s HCG normalised quickly postpartum with no radiological signs of metastatic disease. She has been managed conservatively with monthly HCG surveillance with no signs of recurrence. Twin B remains well with negative HCG surveillance. Although gestational choriocarcinoma can be aggressive and associated with poor obstetric outcomes, it has a good prognosis when diagnosed and treated early. The importance of detailed histopathological placental examination and clinical suspicion for choriocarcinoma following FMH is highlighted by this case.