Imaging description

Primary pulmonary artery sarcomas are rare malignancies, most often “undifferentiated spindle cell sarcomas” or leiomyosarcomas, and are of unknown etiology. They usually arise from the dorsal area of the pulmonary trunk (although they can arise from the right or left pulmonary arteries, pulmonary outflow tract, or pulmonary valve) and are identified on enhanced CT chest as a low-attenuation filling defect (typically solitary) within the lumen of the pulmonary artery. This filling defect may occupy the entire luminal diameter of the artery, may expand the artery, (Figures 55.1–55.3) or may extend through the artery wall [1]. Contrast-enhancement within the tumor has been described, but is not commonly evident on CT [2].

Importance

Because of its rarity and similar imaging appearance to pulmonary embolism, this tumor is often mistaken for pulmonary embolism, resulting in inappropriate therapy such as prolonged anticoagulation or thrombolysis, as well as a delay in accurate diagnosis. Delay in diagnosis results in a generally poor prognosis [3].