Corticotropin-independent Cushing's syndrome caused by an ectopic adrenal adenoma

Although nonsecreting suprarenal embryonic remnants are frequently found in the urogenital tract, adenomatous transformation resulting in glucocortico id excess is a rare phenomenon. We report a case of a 63-yr-old woman that presented with new-onset hirsutism, facial plethora, hypertension, centripe tal obesity, and a proximal myopathy. The 24-h urinary free cortisol excret ion rate was elevated, and the serum ACTH level was suppressed. The patient failed an overnight and low dose dexamethasone suppression test and did no t respond to CRH stimulation. In light of the undetectable baseline morning ACTH levels and the blunt response to CRH, the diagnosis of corticotropin- independent Gushing's syndrome was made. Imaging studies revealed normal ad renal glands and enlargement of a left. pararenal nodule incidentally obser ved 4 yr before the onset of symptoms. Dramatic resolution of symptoms was observed after surgical removal of the 3.5-cm mass. Pathological exam confi rmed adrenocortical adenoma in ectopic adrenal tissue. The case reported he re represents the unusual circumstance in which the development of adenomat ous transformation of ectopic adrenal tissue has been prospectively observe d with imaging studies. It illustrates the importance of considering ectopi c corticosteroid-secreting tumors in the context of corticotropin-independe nt Cushing's syndrome.