ACTH-dependent Cushing’s syndrome is caused by the secretion of ACTH from an ectopic nonpituitary source in 10% to 15% of patients. A small fraction of these cases (approximately 12 cases worldwide) have been attributed to tumors of the thymus gland. Nevertheless, the early identification and treatment of thymic tumors is crucial because they are malignant in 80% of cases and have a 10-year mortality rate of up to 91%. The authors report a case of Cushing’s syndrome from a thymic neuroendocrine carcinoma and review the pertinent literature. A 3- × 4-cm anterior mediastinal mass was found by thin-cut CT in a 27-year-old man being evaluated for Cushing’s syndrome of ectopic origin. It was treated with surgical debulking and prepared to receive localized XRT and possibly octreotide therapy. A review of the literature since 1960 revealed approximately 80 cases of thymic tumors with sufficient clinical and histologic material to draw correlations between histologic grade and clinical outcomes. Treatment always included surgical excision as complete tumorectomy or debulking of the primary or recurring tumor. Radiotherapy and adjuvant octreotide therapy were used with limited success, whereas chemotherapy added no benefit. Despite close follow-up and multifaceted adjuvant therapy, the mortality rate for thymic neuroendocrine carcinoma remains high.
Address correspondence to: Leigh Perreault, M.D., University of Colorado Health Sciences Center, Division of Endocrinology, 4200 E. 9th Avenue, B151, Denver, CO 80206. Phone: 303-315-0791; Fax: 303-315-3273; E-mail: firstname.lastname@example.org