Case Report: Pheochromocytoma Presenting with Cushing’s Syndrome and Hyperglycemia

Abstract

Introduction: Pheochromocytomas are catecholamine-producing neuroendocrine tumors that arise from the adrenal medulla. Pheochromocytomas typically present with uncontrollable or paroxysmal hypertension that can be accompanied by other common initial symptoms, including headache, diaphoresis, arrhythmia, and pallor. Given the morbidity and mortality associated with undiagnosed pheochromocytomas, and their potential for treatment, primary care physicians should consider this tumor type, and other endocrinological phenomena, when evaluating new onset hyperglycemia. Clinical Findings: Patient G was a 76-year-old female who presented in her primary care office with newly uncontrollable hyperglycemia. During initial evaluation, her clinical condition deteriorated rapidly. Her laboratory studies revealed markedly elevated cortisol, adrenocorticotropic hormone (ACTH), and urine metanephrines. Imaging revealed a 3-cm left adrenal mass. Evaluation of ACTH and cortisol levels became complicated by discovery of a lung mass. Clinical Course: Left adrenalectomy led to resolution of hyperglycemia, catecholamine excess, and Cushing’s Syndrome. Tissue pathology of the pheochromocytoma identified ACTH receptor positivity. Conclusions: Pheochromocytoma is a rare but possible cause of Cushing’s Syndrome. Patient G’s resolution of hypercortisolemia after successful resection of the pheochromocytoma indicate the tumor’s role in her hyperglycemia and Cushing’s Syndrome. Despite the well-known association of uncontrollable or paroxysmal hypertension with pheochromocytoma, presenting symptoms vary significantly among patients. The heterogeneity of this neoplasm’s presentation highlights the role primary care can play in building this rare diagnosis into the differential early in the disease course.