Rare case report of main pulmonary artery occupying lesion: pulmonary artery intimal sarcoma.

Background: Pulmonary artery intimal sarcoma (PAIS) is a rare aggressive malignant tumour that is easily confused with pulmonary embolism and poses considerable diagnostic challenges. Case summary: This case report details a 68-year-old male with progressive dyspnoea and chest tightness, initially misdiagnosed as pneumonia and pulmonary thromboembolism. Multimodal imaging, including echocardiography and contrast-enhanced computed tomography, identified an irregular mass within the pulmonary artery causing luminal stenosis, necessitating urgent surgical intervention. Histopathological examination confirmed PAIS. Postoperative recovery without adjuvant chemotherapy resulted in no recurrence or metastasis at a 2-year follow-up. Discussion: This case underscores the pivotal role of imaging in differentiating PAIS from thromboembolic conditions and highlights surgical resection as the cornerstone of treatment. Although the prognosis of PAIS remains poor, complete surgical excision may extend survival, emphasizing the importance of early multidisciplinary collaboration and long-term monitoring. This report advocates for increased clinical suspicion of PAIS in cases of refractory dyspnoea to reduce diagnostic delays.