Primary thymic atypical carcinoid with rare multiple bone metastasis: A case report and literature review

Primary thymic atypical carcinoid (TAC) is a type of extremely rare neuroendocrine tumor. Approximately one-third of patients with TAC tumors are asymptomatic, and no treatments of TAC have been rigorously tested in multicenter clinical trials. To date, there has been no previous case report of TACs with multiple skull metastases. The present report describes a case of a 56-year-old male patient with a primary TAC and multiple axial skeleton metastases, including multiple bilateral metastases to the parietal bones, outer wall of the orbital cavities, and the petrous apex, as well as metastases to the suprasellar region and the clivus. The histological examination confirmed the diagnosis of TAC. Single-photon emission computed tomography, computed tomography and magnetic resonance imaging scans revealed multiple bone metastases. The patient refused chemotherapy and radiotherapy and only accepted alleviative treatment, and died 89 days after diagnosis. This type of cancer is highly malignant with an extremely short natural course and high disease-related mortality. In addition, a review of the literature was performed to provide a reference for proper diagnosis and treatment of TACs.