Ectopic ACTH syndrome caused by thymic neuroendocrine tumor: a case report and literature review

A 36-year-old woman presented with onset of reduced menstrual flow, gradually progressed to typical Cushingoid features with 24-hour urine free cortisol (UFC) increased, low-dose dexamethasone suppression test and high-dose dexamethasone suppression test both not suppressed, adrenocorticotropic hormone (ACTH) increased, and computed tomography (CT) scan of the chest revealed a large mass in the anterior mediastinum. The local hospital administered mediastinal mass resection which afterwards showed type B1 thymoma. The above symptoms were relieved post-operation, and the levels of ACTH and cortisol decreased. Symptoms recurred 5 months after the surgery, with laboratory and imaging suggested possible multiple tumor metastases. The patient was referred to our hospital and was diagnosed with ectopic ACTH syndrome and thymic neuroendocrine tumor with multiple metastases post-operation. After administered mifepristone to antagonize the glucocorticoid receptor, the patient's symptoms improved. The patient also received "etoposide" single-agent chemotherapy, and the symptoms were relieved after 4 months of follow-up. The case showed that complete surgical resection of the primary tumor is the best treatment for ectopic ACTH syndrome, if the primary tumor which cause ectopic ACTH syndrome cannot be completely cured, it is particularly important to control hypercortisolemia and prevent its complications. This article purports to report this case and review the relevant literature.