Silent pheochromocytoma presenting as refractory hyperglycemia without classic adrenergic symptoms

Abstract

Abstract We report the case of a patient with uncontrolled and highly variable hyperglycemia and hypertension. He reported no history of headache, palpitations, or diaphoresis. Abdominal ultrasound and a triphasic computed tomography scan demonstrated a solid mass located medial and superior to the left kidney. Plasma and 24-hour urinary catecholamine levels confirmed a diagnosis of pheochromocytoma. Preoperative preparation included α-adrenergic and β-adrenergic blockade, along with salt and fluid loading. Continuous glucose monitoring and automated insulin delivery were used to stabilize glycemia. After multidisciplinary clearance of the surgery team, the patient underwent laparoscopic left adrenalectomy. Postoperatively, blood pressure and blood glucose normalized, allowing discontinuation of insulin and antihypertensive therapy. Histopathology and genetic testing confirmed a benign adrenal pheochromocytoma. A 3-month follow-up showed normalization of catecholamine levels, allowing the stabilization of blood glucose and blood pressure without medication. This case illustrates how fluctuating glycemia, initially attributed to poor adherence, was in fact secondary to catecholamine excess, underscoring the diagnostic challenge of pheochromocytoma in patients with coexisting metabolic disorders.