Clinical and morphological characteristic of ACTH producing tumors of various localization and the ectopic Cushing’s syndrome

Abstract

Background: Ectopic adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome is a type hypercorticism caused by ectopic production of ACTH and/or its precursors by neuroendocrine tumors (NET) of various localization, such as lung and thymus carcinoids, less frequently those of pancreas and gastrointestinal tract, medullary thyroid cancer, pheochromocytoma, small cell lung cancer, as well as some other tumor types. The wide spectrum of tumors associated with the ectopic ACTH syndrome (EAS) makes their diagnosis and treatment a complicated issue. Materials and methods : The study was done with surgical and diagnostic biopsy samples from 60 patients who had tumors with EAS, 36 (60%) of them being bronchopulmonary carcinoids, 10 (16.7%) thymus carcinoids, 5 (8.3%) pancreatic NETs, 3 (5%) medullary thyroid cancers, 3 (5%) NETs of unknown primary localization, and NET of appendix, cecum and pheochromocytoma (one case of each, i.e. 1.7%, 1.7%, 1.7%). There were 38 female and 22 male patients (1.72:1), with their mean age of 39 ± 14 years (range, 16 to 77 years). We analyzed their clinical data, as well as the results of morphological and immunohistochemical examination of the tumors. Results : According to the World Health Organization classification (2015), typical carcinoids (TC) of the lung were found in 77.8% (28/36) of the bronchopulmonary tumors. 22.2% (8/36) of the bronchopulmonary tumors and all thymus tumors (100%, n = 10) were classified as atypical carcinoids (ATC). Four pancreatic NETs were classified as Grade 2 (G2), 1 as G3, and NETs of the cecum and appendix as G1 and G2, respectively. At present, 29 (48%) patients are living with no relapse (mean age 39 ± 13.5 years), whereas 22 (37%) of patients developed a relapse (mean age 35 ± 13 years), and 15 (25%) of them died, regardless of the age of the patients The history of the disease was not traced in 4 cases. 5-year relapse-free survival of patients with TC of the lung was 85.7% (24/28), of those with ATC 25% (2/8), with ATC of the thymus and medullary thyroid cancer 0%. Mortality from to TC of the lung for the entire follow-up period was 3.6% (1/28), to ATC 12.5% (1/8), to ATC of the thymus and for medullary thyroid cancer 62.5% and 100%, respectively. The patients with NET of the cecum, appendix and pheochromocytoma are alive without progression for 4, 5 and 6 years, respectively. Therefore, the lowest 5-year survival of patients with EAS was observed in medullary thyroid cancer, pancreatic NET and thymus carcinoids: in 100% (3/3), 75% (3/4), and 57.1% (4/7), respectively. Conclusion: The most unfavorable prognostic factors in the EAS are the localization of tumors in the thymus, pancreas and thyroid gland. This indicates the necessity of a differentiated treatment approaches to patients with this syndrome.