Endocrine Abstracts

Introduction: Paraneoplastic Cushing’s syndrome is a rare manifestation caused by the ectopic secretion of ACTH. The tumors involved are almost always malignant, with bronchopulmonary being the most frequent, followed by pancreatic and, more rarely, thymic. Thymic carcinoid tumors are very rare neuroendocrine tumors that often complicate endocrine disorders; they are generally more aggressive and difficult to treat, and typical carcinoid tumors in the thymus normally have no endocrine symptoms. Only some specific cases occur with carcinoid syndrome or Cushing’s syndrome, and it is widely accepted that surgical resection is the only curative treatment for localized lesions.

Observation: This is a 33-year-old male admitted for possible ACTH-dependent Cushing’s disease. He appeared to be quickly developing severe hypercorticism, deteriorated by diabetes, hypertension, and osteoporosis. A 2-day high-dose dexamethasone suppression test suggests ectopic ACTH production. Cervical and thoracoabdominal CT scans indicated oval tissue development in the thymus measuring 11/08 mm with significant heterogeneous enhancement. The patient received a synthetic anticortisolic medication, which restored eucorticism. The thymus was totally resected, and the tumor was removed. The histopathological appearance was that of an atypical carcinoid tumor categorized as T1aNxMx (AJCC 2017). The immunohistochemistry profile was positive for Chromogranin A and Synaptophysin with a high ki67 (40%). The postoperative prognosis was excellent, with remission of Cushing’s syndrome and good glycemic and blood pressure management without therapy.

Conclusion: As secretory thymic tumors are very rare, their discovery at an early stage and their resection remain the only solutions for treating paraneoplastic Cushing’s syndrome.