ABSTRACT Objective: To present a rare case of primary paragan- glioma of the lung, which caused the syndrome of ectopic adrenocorticotropic hormone (ACTH) hypersecretion. Methods: The clinical, biochemical, and imaging findings in this case are described, and the pathologic fea- tures of the resected tumor tissue are depicted. In addition, the related literature on paragangliomas is reviewed. Results: In a 39-year-old woman with hypertension, weight gain, and easy bruising, laboratory studies showed hypercortisolemia, high plasma ACTH levels, and sup- pression of cortisol by high-dose dexamethasone. An indi- um-labeled octreotide whole-body scan disclosed a tumor in the left lower lung field. Thoracoscopic wedge resec- tion of the pulmonary mass was performed. Postoperative microscopic findings and immunohistochemical stains revealed nests of rounded and polyhedral cells and S-100 protein-positive sustentacular (supporting) cells, charac- teristic of paraganglioma. Conclusion: This unusual case of Cushing’s syn- drome was attributable to an ACTH-secreting primary pulmonary paraganglioma. (Endocr Pract. 2004;10:424- 428) INTRODUCTION Cushing’s syndrome is a well-known constellation of features that are a result of prolonged endogenous or exogenous glucocorticoid excess. Most endogenous cases of Cushing’s syndrome are due to either adrenocorti- cotropic hormone (ACTH)-secreting pituitary tumors or nonpituitary neuroendocrine tumors that result in adrenal hyperplasia and hypersecretion of cortisol (1). The secretion of ACTH by nonpituitary neuroen- docrine tumors, often referred to as the syndrome of ectopic ACTH hypersecretion, accounts for 10 to 15% of cases of ACTH-dependent Cushing’s syndrome. These neuroendocrine tumors are of neural crest origin (2). Small cell carcinoma of the bronchus constitutes almost half of all causes of ectopic ACTH secretion. Other known causes of the syndrome are bronchial carcinoid tumor, thymic carcinoid tumor, pancreatic islet carcinoma, medullary carcinoma of the thyroid, pheochromocytoma, and other miscellaneous tumors (3,4). Only a few reports have identified paraganglioma as a cause of the syndrome of ectopic ACTH hypersecretion (5-12). On the basis of an extensive review of the litera- ture, we found only one previously reported case of an ACTH-secreting primary pulmonary paraganglioma (10). In this report, we present a case of a 39-year-old woman with Cushing’s syndrome, which proved to be attributable to an ACTH-secreting primary paraganglioma of the lung. CASE REPORT A 39-year-old woman presented with a 4-year history of depression, hypertension, a 34-kg weight gain, weak- ness, easy bruising, hyperpigmentation, and oligomenor- rhea. She denied ingesting any corticosteroid-containing medications. Her medications at the time of evaluation were as follows: ethinyl estradiol/norethindrone (35 μg/0.4 mg), buproprion (150 mg daily), hydrochlorothi- azide (50 mg daily), bisoprolol/hydrochlorothiazide (5 mg/6.25 mg daily), and amlodipine (5 mg daily). She reported a 30-pack-year history of tobacco use. Physical examination revealed a blood pressure of 142/104 mm Hg, heart rate of 80 beats/min, weight of 78.9 kg, and height of 160 cm. She had a pronounced cushing- oid appearance, manifested as central facial rounding, central weight redistribution, notable thickening of the cervicodorsal and supraclavicular fat pads, numerous ecchymoses, diffuse hyperpigmentation of the skin, hyperpigmented scars, evidence of moderate proximal ECTOPIC ADRENOCORTICOTROPIC HORMONE HYPERSECRETION DUE TO A PRIMARY PULMONARY PARAGANGLIOMA Kathryn McCrystal Dahir, MD, 1 Adriana Gonzalez, MD, 1 Monica P. Revelo, MD, 1 S. Rafeeq Ahmed, MD, 2 John R. Roberts, MD, 1 and Lewis S. Blevins, Jr., MD 1 Submitted for publication January 25, 2004 Accepted for publication March 25, 2004 From the 1 Vanderbilt University School of Medicine, Nashville, Tennessee, and 2 Endocrinology and Diabetes Clinic, Florence, Alabama. Address correspondence and reprint requests to Dr. L. S. Blevins, Jr., 715 PRB, Vanderbilt University Medical Center, Nashville, TN 37232-6303. © 2004 AACE. 424 ENDOCRINE PRACTICE Vol 10 No. 5 September/October 2004 Case Report Abbreviations: ACTH = adrenocorticotropic hormone; CRH = corti- cotropin-releasing hormone