Fig. 3

A A mass was observed within the main pulmonary artery and the branches of the left and right pulmonary arteries. The mass appeared soft and dark in color. B Postoperative pathology revealed a spindle cell tumor, which was diagnosed as a sarcoma based on the combination of immunohistochemistry and genetic testing. C, D Postoperative echocardiography: there was an irregular hypoechoic mass measuring approximately 16 × 9 mm detected at the level of the pulmonary valve annulus, which was closely related to the pulmonary artery valve. E Postoperative CTPA: membranous structures were observed in the main pulmonary artery and left pulmonary artery