[Atypical Thymic Carcinoid:Report of a Case].

A 79-year-old man was referred to our hospital because of an abnormal shadow observed on a chest radiograph. Computed tomography (CT) revealed a 7 cm mass in the right thoracic cavity. Additionally, T1-weighted, T2-weighted, and contrast-enhanced magnetic resonance images (MRI) exhibited a heterogenous mass in the same area. An extensive unenhanced area with a reticular septum was noted within the mass. An open axillary thoracotomy was performed. Postoperative pathological diagnosis was atypical thymic carcinoid. No clinically evident recurrence was observed at 19 months after treatment. Thymic carcinoid is highly malignant with a poor prognosis. Imaging findings are characterized by a heterogeneous tumor interior and the presence of reticular septum. Based on our experience with the current case, thymic carcinoid should be deliberated in the differential diagnosis, and an early resection should be considered.