Normotensive incidental pheochromocytoma: report of a rare case with a brief review of literature

Abstract

Normotensive pheochromocytoma is a rare clinical entity that poses a pre-operative diagnostic challenge. Especially so, when the patient is clinically and biochemically silent. Initially diagnosed as incidentaloma, a biochemical panel of adrenal hormonal levels, cross sectional imaging and metabolic scan are required for pre-operative diagnosis. We present a rare case of a normotensive incidentally discovered large left adrenal pheochromocytoma unfolding to us as a histological surprise along with a brief review of the literature. 41-year-old gentleman, non-hypertensive and non-diabetic, coming from a remote village, who was admitted to our hospital with a provisional diagnosis of an adrenal incidentaloma. He had a 6-month-old abdominal ultra-sonogram report which stated a 47 × 36 mm left suprarenal region mass. Except having complaints of a vague upper abdominal pain since last 1 year he gave no history suggestive of headaches, palpitations, excessive sweating or recent changes in weight. There was no family history of neurofibromatosis or any thyroid, parathyroid, kidney or other abdominal tumors. On examination he had an average built and nutritional status, with no cushingoid features or any dermatological abnormalities. In supine position and upon standing for 2 minutes his baseline pulse rate and blood pressure (BP) were 76 beats/min and 132/80 mm Hg, and 90 beats/min and 126/76 mm Hg respectively. There were no ophthalmological abnormalities or neck lumps, abnormal chest or abnormal abdominal findings. Intensive BP monitoring did not reveal any paroxysmal hypertensive peaks. In the absence of hypertension and other classical clinical features of pheochromocytoma coupled with a normal plasma metanephrine level, it was a sort of histological surprise for us that the lesion turned out to be a pheochromocytoma. Although we did preload the patient with intravenous fluids 36 hrs prior to the surgery but intraoperatively the transient increase in blood pressure while handling the tumor hinted us towards the possibility of a pheochromocytoma.

Keywords

• pheochromocytoma
• normotensive incidental pheochromocytoma
• adrenal incidentaloma
• silent pheochromocytoma
• asymptomatic pheochromocytoma