Cushing syndrome from an ACTH-producing pheochromocytoma or paraganglioma: structured review of 94 cases

Adrenocorticotropic hormone-producing pheochromocytomas/paragangliomas are rare neuroendocrine tumors that co-secrete excess catecholamines and adrenocorticotropic hormone, resulting in Cushing syndrome (CS). This review aims to summarize important patient characteristics, investigations, and outcomes in all cases reported in the English literature. A literature search was conducted to identify all English-language case reports and case series describing adrenocorticotropic hormone-producing pheochromocytomas/paragangliomas. Relevant characteristics were systematically recorded. Cases that did not provide definitive evidence of an adrenocorticotropin (ACTH)-producing pheochromocytoma/paraganglioma were excluded. Our search strategy identified 93 published cases that met the inclusion criteria. We additionally reported one patient for a total of 94 cases. Details related to patient characteristics, laboratory data, and outcomes were commonly underreported. The median age was 47 years, and females accounted for 72% of cases. A cushingoid appearance was reported in 82% of patients, and hypertension in 86%. Infections were reported in 23% of patients. Urinary metanephrines were elevated at least three-fold above normal in 74% of cases. ACTH levels were high in 88% of patients and inappropriately normal in 12%. The median 24-hour urinary cortisol was 21-fold the upper limit of normal. Adrenalectomy was performed in nearly all patients, with 88% achieving a cure for both catecholamine and glucocorticoid excess. A total of 11 patients died. Metastases were uncommon (6%). Adrenocorticotropic hormone-producing pheochromocytomas/paragangliomas are associated with considerable morbidity and mortality. It should be considered in the diagnostic workup of all patients with ectopic CS. Surgical cure is achieved in most patients, and infections are the leading cause of peri-operative mortality.