A Rare Case of Pulmonary Artery Intimal Sarcoma Diagnosed Antemortem by Endoscopic Ultrasound-Guided Fine-Needle Aspiration.

Primary pulmonary artery sarcoma (PPAS) is a rare malignancy often misdiagnosed as pulmonary thromboembolism. Antemortem diagnosis is often difficult because of the tumor's deep intravascular location and challenges in obtaining tissue samples. We report a 72-year-old man with pulmonary artery intimal sarcoma diagnosed antemortem using endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Contrast-enhanced computed tomography demonstrated a heterogeneously enhancing intraluminal pulmonary artery lesion, and positron emission tomography/computed tomography revealed intense fluorodeoxyglucose uptake (SUVmax 18.4). Histopathological examination showed atypical spindle-shaped cells positive for vimentin and focally positive for α-smooth muscle actin, consistent with intimal sarcoma. The patient received radiation therapy and doxorubicin-based chemotherapy but died 25 weeks after admission. Consistent with previous reports, this case illustrates the aggressive clinical course and diagnostic challenges of PPAS. It also highlights the importance of considering PPAS in patients with atypical pulmonary embolism and demonstrates the utility of EUS-FNA as a minimally invasive approach for obtaining a definitive diagnosis of centrally located pulmonary artery tumors.