Conduction system metastasis in a patient with carcinoma oesophagus

A young man in his 30s presented to us with multiple episodes of syncope and exertional dyspnoea for the last 2 weeks. He was diagnosed with squamous cell carcinoma of the lower one-third of the oesophagus in 2021 for which he was treated with neoadjuvant chemoradiotherapy, followed by McKeown oesophagectomy. At 2-year follow-up, he had developed a soft tissue swelling in the scalp, which was diagnosed as a tumour recurrence and radiotherapy was initiated. During this period, he presented to the emergency department with multiple episodes of syncope. The patient had bradycardia with a heart rate of 45 beats per minute (bpm). A 12-lead ECG showed complete heart block with wide QRS escape at a rate of 45 bpm. Cardiac MRI revealed a focal T1/T2 hyperintense lesion in the basal interventricular septum, showing central necrosis with peripheral enhancement on early and delayed phase imaging, suggestive of an intracardiac metastasis. Cardiac fluorodeoxyglucose positron emission tomography scan revealed uptake in the basal interventricular septum corresponding to the site on the MRI. The patient was initially kept on temporary pacemaker support followed by implantation of a transvenous dual chamber pacemaker.