Pleural cavity angiosarcoma arising in chronic expanding hematoma after pneumonectomy.

A 52-year-old man received a left pneumonectomy for pulmonary squamous cell carcinoma without signs of recurrence after surgery. At age 68 years, a capsulated huge mass developed in the left pleural cavity, which was diagnosed as chronic expanding hematoma. Two years and 8 months after detection, the lesion began to invade the chest wall, and 10 months later, the patient died of active bleeding and direct compression of the heart by the lesion. At autopsy, the left thoracic cavity was occupied by a cystic and hemorrhagic mass infiltrating into the surrounding structures. In addition, scattered tumorous nodules were observed in the right lung. Histologically, angiosarcoma with irregularly anastomosing vessels lined with atypical endothelial cells was noted in the chronic expanding hematoma. The final diagnosis was pleural cavity angiosarcoma arising in chronic expanding hematoma and its metastases to the right lung.