Primary Thymic Mucinous Adenocarcinoma: A Case Report Focusing on Radiological Findings and Review of the Literature

Primary thymic mucinous adenocarcinoma is a very rare disease. Its clinical findings are not well known. Its prognosis is poor. We present a case of primary thymic mucinous adenocarcinoma in a 60-year-old woman. The patient visited the emergency room with dysarthria as a chief complaint, and a mass was found in the occipital bone and petrous apex in brain computed tomography (CT) and magnetic resonance imaging (MRI). The lesion was considered metastasis, and body CT evaluation was performed to find the primary origin. In CT, a large peripheral enhancing mass with central low attenuation and calcification was found in the anterior mediastinum. Pathologic confirmation of the anterior mediastinal mass was done by percutaneous needle biopsy procedure. The patient was diagnosed with primary thymic mucinous adenocarcinoma. We also reviewed and analyzed previous literature focusing on radiologic findings. The possibility of primary thymic mucinous adenocarcinoma should be considered if a large mass with a heterogeneous enhancement pattern is accompanied by adjacent tissue involvement, associated thymic cyst, or calcification.