Chronic expanding hematoma in the chest is identified as a specific type of chronic empyema. We encountered a case of chest chronic expanding hematoma presenting as a huge mass, which compressed the heart, trachea and esophagus. The disease was recognized as a cause of aspiration pneumonia and was successfully treated by surgical resection. Computed tomography revealed a large area of calcifications at the periphery of the mass. Magnetic resonance T2-weighted imaging indicated the mosaic patterns of various signal intensities as specific features of chronic expanding hematoma. Imaging diagnosis showed good correlation with pathology of the disease.