Intimal sarcoma of the pulmonary artery : Report of an autopsy case

Primary pulmonary artery sarcomas (PASs) are rare and lethal tumors. They are easily misdiagnosed as chronic pulmonary embolism, mediastinal mass or tumor emboli, which delay a proper treatment. Although the advanced technologies are now increasingly being used, their diagnosis is usually hard to establish preoperatively at the present time. We report here a case of a 68-year-old female with PAS with lung metastases, who firstly presented with symptoms of common cold and anemia. Although a PAS had been suspected, the final diagnosis of pulmonary intimal sarcoma was made only postoperatively by histological and immunohistochemical examination. The patient died 8 months after the operation because of tumor growth progression, despite adjuvant chemotherapy and radiation therapy. Although pulmonary intimal sarcomas are usually of poorly differentiated mesenchymal malignancy, most reported cases are immunohistochemically positive for vimentin, α-smooth muscle actin (SMA), and/or desmin, therefore resembling leiomyosarcomas. However, the diagnosis of leiomyosarcoma should not be made on the basis of immunostains in the absence of typical morphologic features, and PAS, like the present case, should be more appropriately classified as intimal sarcoma according to the new WHO Classification of Tumours of Soft Tissue and Bone published in 2002.