A 65-year-old man was admitted for evaluation of slowly growing mass shadow in the right lower lung field on chest X-ray film. He had undergone right upper lobectomy for pulmonary tuberculosis 37 years before. As we could not rule out a suspicion of mediastinal tumor, thracotomy was performed. Histological examination of the resected mass showed a hematoma surrounded by dense fibrotic tissue. And the mass was resultantly diagnosed as chronic expanding hematoma. The mechanism of chronic expanding hematoma is unclear. In our review of the Japanese literatures, only 10 cases including this one, resected more than twenty years after the initial trauma or operation, could be found.