With the vast advancement in ultrasound technologies, the capability to visualize and diagnose structural fetal abnormalities as well as congenital birth defects has improved tremendously. Along with these advances, the growing availability of 2D, 3D and 4D ultrasound technology has also increased public access to these ultrasound services. One of the rare abnormality includes fetal tumour of the head and neck. Prenatal diagnosis of these tumours or masses is of upmost importance in planning antenatal care of high-risk pregnancy and perinatal management. The differential diagnosis of fetal head and neck tumour includes lymphangiomas and haemangiomas, cervical teratoma, tumours of the gingiva and lymphatic venous malformations.

We report the course and outcome of an in-vitro fertilization (IVF) pregnancy referred to us at 33 weeks with a prenatal diagnosis of large cystic fetal neck mass made since 20 weeks of gestation. The patient was in her third pregnancy with pre-implantation genetic diagnosis (PIGD) made prior to embryo transfer. She was diagnosed with gestational diabetes mellitus at 30 weeks of gestation and started on oral hypoglycaemic agent. Her two previous pregnancies were also conceived by assisted reproductive technique with the first via intrauterine insemination technique and second pregnancy via IVF. Both pregnancies ended with caesarean section. Ultrasound done showed multicystic mass at lateral aspect of neck with septation and has a thin overlying skin. There was no solid component but the mass has increased vascularity and polyhydramnios was present. Narrowing of the trachea was seen with no tracheal deviation at follow up scans, which was confirmed by the fetal MRI findings. In view of the complexity of the case, a multidisciplinary meeting was initiated involving the obstetricians, neonatologists, paediatric surgeons, paediatric ENT specialists, anaesthetists and radiologist to discuss the plan for delivery. Caesarean section with Ex-Utero Intrapartum Treatment (EXIT) was performed at 34 weeks gestation and endotracheal intubation using 2.0 mm tube was performed at delivery followed by tracheostomy. The baby underwent injection of OK-432, a sclerosing agent at day 15 and day 33 of life. However there was no response seen.