Pheochromocytoma: An Uncommon Presentation of an Asymptomatic and Biochemically Silent Adrenal Incidentaloma

Pheochromocytomas are rare tumours originating from the chromaffin tissue. The clinical manifestations are variable and are not specific; as a result, pheochromocytomas often imitate other diseases. The diagnosis is usually established by biochemical studies, i.e., the measurement of catecholamines or their metabolites in urine or plasma, followed by radiographic and scintigraphic studies for localisation. Surgical removal of the tumour is the preferred treatment. We report a 30-year-old woman presenting with an adrenal incidentaloma that was 7.6 × 5.3 × 4.8 cm in size on an abdominal computed tomography scan. Investigations for adrenal hormones, including a low- dose dexamethasone suppression test, plasma aldosterone level, 24-hour urinary metanephrine and vanillylmandelic acid levels, and plasma metanephrine level were all within the normal ranges. During the surgical resection, the patient had a hypertensive spell. Surgery was postponed, and the blood pressure was adequately controlled with α blockers, followed by β blockers. After 2 weeks, the surgery was followed by a pathological biopsy that confirmed the pheochromocytoma diagnosis.

Keywords
adrenal incidentaloma, catecholamines, hypertension, pheochromocytoma, scintigraphy