[Bilateral Pneumothorax due to Pulmonary Metastasis from Angiosarcoma of the Forehead；Report of a Case].

Angiosarcoma is rare but highly malignant tumor arising from vascular endothelial cells. A 85-year-old man with difficulty in breathing for 3 days was referred to our hospital. He had a history of angiosarcoma of forehead 4 months before. A chest computed tomography (CT) scan showed left pneumothorax with multiple cystic changes and ground grass attenuations of bilateral lungs, which had obviously increased in recent 2 months. Pulmonary metastases with secondary pneumothorax was highly suspected by the serial CT findings. He was treated with tube thoracostomy and the instillation of a sclerosing agent (minocycline hydrochloride 200 mg). Seven weeks after his initial presentation, he died from obstructive pneumonia and an autopsy was held. Histologic examinations revealed that the tumor foci were peripheral, multiple and generally formed nodules. These cells were cluster differentiation (CD)31 and CD34 positive and negative for calretinin, cytokeratin, carcinoembryonic antigen (CEA), thyroid transcription factor (TTF-1) and epithelial membrane antigen (EMA). These findings were compatible with pulmonary metastases of angiosarcoma of forehead.