A Rare Case of Multicentric Primary Pulmonary Artery Sarcoma: Eliminating the Masquerade with Multimodality Imaging

Abstract

A 68-year-old male presented with a short history of exertional dyspnea and a provisional diagnosis of pulmonary thromboembolism was made. However, chest radiograph and further investigations in the form of computed tomography pulmonary angiogram, magnetic resonance imaging of thorax, and whole body fluorodeoxyglucose (FDG) positron emission tomography-computed tomography revealed a large mass arising from the distal left pulmonary artery extending into adjacent lung and another lesion near the root of the main pulmonary artery, both of which showed post-contrast enhancement and intense FDG uptake. Tissue sampling by transthoracic computed tomography-guided biopsy and immunohistochemistry confirmed the diagnosis of pulmonary artery angiosarcoma. Here, we present such a case of very rare occurrence which, in view of multicentricity and substantial extension into adjacent lung, is the first of its kind to be reported, to the best of our knowledge.

Keywords: PAS; angiosarcoma; pulmonary artery sarcoma; sarcoma; wall eclipsing sign.

Fig. 1

Frontal chest radiograph shows a well-defined rounded opacity in the left parahilar region (black arrow).

Fig. 2

( A, B ) Axial computed tomography pulmonary angiogram (CTPA) images show patchy minimal peripheral enhancement (white arrows) of the large mass lesion with Hounsfield Unit (HU) of 28 and 41 in the early and delayed phases, respectively, occluding the distal left pulmonary artery. ( C ) Axial CTPA image shows minimally enhancing filling defect in the root of the pulmonary artery with HU of 61 (black arrow). ( D ) Coronal maximum intensity projection image showing normal right pulmonary arterial tree (black arrow) and complete nonopacification distal left PA onward with corresponding left lung oligemia (white arrows).

Fig. 3

Magnetic resonance imaging thorax. Arrows show the two lesions appearing isohypointense on T1-weighted image ( A ), heterogeneously hyperintense on T2-weighted image ( B ), with central gradient recalled echo hypointensity ( C ) and hyperintense on PDFS images ( D ).

Fig. 4

Post-contrast magnetic resonance images: ( A, B ) Medial and central lesional enhancement (white arrows) in the arterial phase with progressive diffuse enhancement on the delayed phases with occlusion of the left main pulmonary artery distally. ( C ) Small enhancing lesion within the root of the main pulmonary artery (arrow). ( D ) Classical demonstration of left lung oligemia secondary to occlusion of the left main pulmonary artery (arrow).

Fig. 5

Fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT): ( A ) Initial and ( B ) delayed. Arrows show a large lesion with heterogeneous increased uptake and another lesion at the root of the pulmonary artery, with increased uptake on delayed images. Arrowhead marks central non-FDG avid area of necrosis within the lesion.

Fig. 6

Computed tomography (CT)-guided biopsy of the mass lesion by posterior approach. ( A ) Needle tract. ( B ) Post-biopsy plain axial CT with air foci within (arrows).