Inoperable solitary intracardiac pheochromocytoma: role of MIBG scan and treatment

Full text: A 23-year-old female presented for investigation of a clinically diagnosed pheochromocytoma. She has experienced five years of worsening symptoms of elevated blood pressure, flushing, sweating, intermittent head aches, and recently elevated urinary catecholamine. A whole body I-123 mIBG scan displayed uptake in the thorax, probably cardiac in origin, there were no other abnormalities CT and MRI demonstrated a 9cm-diameter mass, occupying most of the right atrium and ventricle. A cardiac angiogram was performed and the tumour was supplied by branches from the right coronary and left circumflex arteries. Exploratory median sternotomy was undertaken, however, the tumour was inoperable and further surgical intervention was abandoned. Due to the patient's limited therapeutic options, a therapy dose of I131 mIBG was considered and a repeat I123 mIBG scan was arranged for dosimetry prior to treatment. Sequential whole body scans were acquired until the activity in the patient was < 10% of the original activity and the tumour uptake was calculated to be only 3% of the injected dose (if injected intravenously). Treatment options at this stage included intravenous or intracoronary therapeutic mIBG and heart-lung transplant. The patient is currently pregnant and is awaiting treatment. This case displays an unusual type of pheochromocytoma and highlights potential advantages of therapeutic Nuclear Medicine. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc