Thymic endocrine tumor is a rare, malignant, primary thymic neoplasm originating from neuroendocrine cells, presenting as a mass within the anterior mediastinum. Patients typically present with nonspecific symptoms, such as chest pain, cough, shortness of breath, or in some cases, superior vena cava syndrome, although patients could be asymptomatic during the early stages or present with multiple endocrine neoplasia type I. Ectopic production of ACTH and serotonin can lead to Cushing syndrome and carcinoid sydrome, respectively. The disease is thymic neuroendocrine tumor (MONDO_0019964). Also known as: neuroendocrine neoplasm of thymus, thymus NET, thymus neuroendocrine neoplasm, thymus neuroendocrine tumor, thymus neuroendocrine tumor, well differentiated, low or intermediate grade, thymus neuroendocrine tumour.