Methods Retrospective review of case notes and Badger discharge summary of an infant admitted to a level 3 district general hospital NICU in 2017. Results Baby F is a 36 weeker born in good condition to a multiparous mother with an unremarkable antenatal history. Admitted from postnatal ward at 2 hours old due to respiratory distress and hypoxia.Deteriorated despite non-invasive ventilation thus intubated for surfactant administration and conventional ventilation. Chest x-ray (CXR) revealed large pneumomediastinum. Required 100% fraction of inspired oxygen (FiO2) thus changed to high frequency oscillator ventilation and started inhaled nitric oxide (iNO) for presumed persistent pulmonary hypertension of the newborn (PPHN) Echocardiogram by attending neonatologist showed a small right ventricle and an echogenic mass on the TV causing obstruction and tricuspid regurgitation (TR). Transferred to the regional cardiothoracic centre on prostaglandin infusion for suspected tricuspid atresia.Discussed at cardiothoracic multidisciplinary team meeting. Differential diagnoses: