Pulmonary Artery Intimal Sarcoma Presenting as Pulmonary Embolism and Pulmonary Hypertension: A Case Report and Literature Review

Introduction Pulmonary artery intimal sarcoma (PAIS) is a rare mesenchymal malignancy often misdiagnosed as pulmonary embolism (PE) or chronic thromboembolic pulmonary hypertension (CTEPH). Case Presentation A 40-year-old woman with no chronic illness, prior venous thromboembolism, or known thrombophilia, and no relevant family history of venous thromboembolism or a known clotting disorder, presented with progressive dyspnea and pleuritic chest pain. Imaging showed severe pulmonary hypertension, a central mass-like right pulmonary artery filling defect extending to the pulmonary trunk bifurcation, and a right upper lobe nodule. The presentation was initially managed as pulmonary embolism; malignancy and tissue diagnosis were not initially discussed. Symptoms persisted despite anticoagulation, and catheter-based thrombolysis failed because the lesion could not be traversed. Biopsy of the pulmonary nodule showed a poorly differentiated sarcoma compatible with intimal sarcoma, and integrated radiologic, pathologic, and multidisciplinary assessment supported primary PAIS with pulmonary metastases. The tumor was considered unresectable because of extensive bilateral central pulmonary arterial involvement and pulmonary metastatic disease. Palliative chemotherapy was initiated. Discussion PAIS should be suspected when presumed PE shows an expansile mass-like defect, pulmonary nodules, severe pulmonary hypertension, or non-response to anticoagulation, prompting biopsy.