Clinicopathological and immunohistochemical features of pulmonary artery sarcoma: A report of three cases and review of the literature.

Pulmonary artery sarcoma (PAS) is an extremely rare and highly malignant tumor that originates in the pulmonary artery. The majority of reported cases of PAS are confirmed by pathological examination subsequent to surgery or by autopsy. The present study reports the clinicopathological characteristics and immunohistochemical phenotypes of three cases of PAS, and aims to facilitate the identification of this lethal disease. In the present study, the data from clinical, histopathological and immunohistochemical examinations of three patients with PAS, whose diagnoses were confirmed by surgical biopsy conducted at the Beijing Anzhen Hospital (Beijing, China) between 2008 and 2012, were retrospectively analyzed. The patients (two women and one man; average age, 41.3 years old) presented with dyspnea on exertion. In addition, two of the patients experienced chest tightness, and one patient experienced intermittent syncope. Computed tomography pulmonary angiography revealed that two of the patients possessed a filling defect in the main, left and right pulmonary arteries, and one patient possessed a filling defect in the right upper pulmonary artery. Macroscopically, the PAS appeared as a mucoid intraluminal or nodular sessile mass spreading along the pulmonary artery. Microscopically, the tumor consisted of spindle cells with fascicular and storiform patterns, and was accompanied by necrosis and stromal myxoid changes. Immunohistochemically, vimentin, desmin and cluster of differentiation 34 were highly expressed in the patient that was diagnosed with intimal sarcoma, while vimentin and α-smooth muscle actin were highly expressed in the other two patients, who were diagnosed with leiomyosarcoma. PAS is often misdiagnosed due to nonspecific clinical manifestations and radiological features. Therefore, the diagnosis of PAS should be based on typical morphological features and immunohistochemical analysis of the tumor tissue.