In 1999 a healthy 73-year-old woman was found to have an incidental solid lesion in her right adrenal gland on CT (2.0 cm diameter). She had intermittent mild systolic hypertension but no postural symptoms and was not taking any medications. She gradually developed sustained hypertension and was commenced on amlodipine in 2005; irbesartan was added in 2007.
Her mother had hypertension and died of a cerebrovascular event aged 76 years; her two brothers were alive and well. Initial endocrine investigations, including 24-hour urinary fractionated catecholamines, were normal.
Follow-up CT scans were initially unchanged but in 2003 the lesion’s diameter was 2.3 cm and it had developed a small cystic component. By 2010, it had grown to 2.7 cm (3.2 cm on coronal views), with further cystic degeneration/necrosis and a reduction in its absolute contrast washout from 71% (in 2006) to 12%.
Adrenal function tests were repeated in 2010; plasma and 24-hour urinary metadrenaline and normetadrenaline and urinary adrenaline were elevated. I-123 MIBG scan showed avid isotope uptake by the adrenal mass. Pheochromocytoma was diagnosed and the patient’s anti-hypertensive medications were progressively changed to phenoxybenzamine and propranolol.
She underwent laparoscopic right adrenalectomy in early 2011. Histopathology confirmed a pheochromocytoma, with a diameter of 4.8 cm and focal extension into peri-adrenal adipose tissue. She has remained normotensive post-operatively, with normal plasma and urinary catecholamine levels. In 2013 she underwent successful total knee replacement surgery and continues to live independently. She does not have any children, nephews or nieces and has declined genetic testing.
Pheochromocytomas may pass through a “pre-biochemical” stage of development in which they are asymptomatic and their catecholamine secretion is not elevated1. This patient’s non-functioning adrenal lesion evolved into a symptomatic pheochromocytoma over a lengthy period, indicating the need for ongoing follow-up of small and initially non-functioning adrenal “incidentalomas”.