A diagnostic dilemma in diagnosing and managing an incidental phaeochromocytoma

Incidental adrenal tumours are a common radiological finding. Phaeochromocytomas, though rare, are very important not to be missed, as the consequences could be fatal. Urinary catecholamines and metanephrines measurement is a commonly used method of screening for phaeochromocytomas. We report a patient who had a phaeochromocytoma presented as an incidental adrenal mass on abdominal CT during investigations for recurrent chest infections. The patient had symptoms suggestive of catecholamines excess and hypertension. Repeated urinary catecholamines measurements, plasma catecholamines, 24-hour urinary catecholamines and 24-hour urinary metanephrines all were normal. MIBG scan showed increased uptake in the adrenal mass. Histological examination of the adrenal mass was consistent with phaeochromocytoma. Removal of the adrenal mass resulted in normalisation of blood pressure and abolishing of the patient's symptoms. This case highlights the difficulty in deciding on further management of patients presenting with an adrenal incidentaloma. This case also highlights the difficulty in diagnosing phaeochromocytoma and represents a reminder that plasma and urine catecholamines measurements could be normal in patients with symptomatic phaeochromocytoma. This case also highlights that MIBG scan could reveal a phaeochromocytoma despite absence of biochemical markers.