Pulmonary artery intimal sarcoma presenting as lung mass

This report describes a case of incidental lung lesions, discovered during investigations for symptomatic aortic stenosis. The chest computed tomography pulmonary angiogram (CTPA) revealed the presence of two lung masses in the background of longstanding pulmonary thromboembolic disease. Left upper lobectomy was performed and the histopathological examination of the lung masses showed a high-grade spindle cells malignancy with areas showing tumour cells intraluminally in large and small vessels causing partial and complete luminal occlusion. The Fluorescence in situ hybridization (FISH) study showed Mouse double minute 2 homolog (MDM2) amplification, which was consistent with the diagnosis of Pulmonary Artery Intimal Sarcoma (PAS). We report the rare entity of PAS presenting as a lung mass and some potential pitfalls in diagnosis.