A 30-year-old man was hospitalized with edema, polyuria, and abnormalities in taste. ACTH and cortisol levels at admission were markedly elevated, even after attempted suppression with 8 mg dexamethasone. A thoracic-abdominal CT revealed an anterior mediastinal lesion and hyperplasia of both adrenal glands. After excision of the mediastinal mass, which confirmed the presence of a carcinoid thymic tumor, the patient became totally asymptomatic, with normal ACTH and cortisol levels. A carcinoid thymic tumor has a poor prognosis, especially when it is associated with Cushing's syndrome. Most patients will present recidivism or metastasis within 5 years after surgery. However, the low number of cases available for analysis makes it difficult to establish optimum therapeutic approaches.