A case of chronic expanding hematoma presenting as a huge mass in the pleural cavity.

We report a case of a huge chronic expanding hematoma completely removed by surgery. A 71-year-old man was found to have a 3-cm-diameter round nodule in the posterior mediastinum seven years previously. He was not administered any treatment because he did not have any other serious symptoms. There was nothing in his history that could be related to his present condition, such as thoracic surgical treatment or tuberculosis. The massive tumor in the left pleural cavity grew, compressing the left lung and heart gradually in the past seven years. Cytological examination of a needle biopsy specimen showed only erythrocytes with a few infiltrating inflammatory cells. Moreover, his preoperative histopathological analysis did not reveal any significant findings. Therefore, he underwent complete resection of the hematoma including the fibrous capsule and left lower lobectomy. Severance of abundant new vascularizations caused massive bleeding. The postoperative course was uneventful. There was no recurrence in the two years. In cases of gradual growth of a mass without indications of malignancy, we should consider the existence of a chronic expanding hematoma even in patients without a history of thoracic operation or tuberculosis.