PMC9053012_01
Radiology characteristics of Case 1. (a) An axial image from a contrast-enhanced chest computed tomography (CT) shows a complete filling defect in the right main pulmonary artery (arrows). It is atypical for bland pulmonary thromboembolic disease to result in unilateral occlusion of a main pulmonary artery. (b) A coronal maximum intensity projection (MIP) image demonstrates dilated bronchial arteries (arrows) coursing towards the right lung. (c) A frontal chest radiograph shows diminutive right hilar/pulmonary vessels compared to the left. (d) A VQ scan demonstrates the absence of perfusion in the right lung. Likewise, both CT images show diminished blood flow in the right lung
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A ventilation perfusion (VQ) scan showed a complete absence of perfusion of the right lung (Figure 1). Our review of the outside CTA revealed an infiltrating mass-like lesion that completely occluded the right main pulmonary artery (PA) with possible arterial wall involvement (Figure 1).
Case 1. Macroscopic examination (a) shows a mass-forming lesion. H&E (b) reveals prominent plasma cells and lymphohistiocytic infiltrate. The scattered spindle cells are positive for SMA (c), and negative for ALK (d). IgG highlights markedly increased plasma cells (e), with only scattered immunopositivity for IgG4 (f); (b-f) x200 original magnification. H&E, hematoxylin and eosin; SMA, smooth muscle action
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Grossly, the resected right PA measured 8.0 cm in size and showed a friable dark brown soft tissue mass filling the lumen (Figure 2a). Microscopic sections of these vascular contents revealed dense lymphoplasmacytic infiltrate with a few foci of bland-appearing spindle cell proliferation (Figure 2b). The plasma cells were polytypic by immunostain, with less than 30% positive for IgG4 (Figure 2c-f).
PMC9053012_02
H&E morphology of Case 2 (a), 3 (b), 4 (c), and 5 (d) shows similar histology to that seen in Case 1, except more confluent spindle cells in Case 5 (d); x200 original magnification. H&E, hematoxylin and eosin
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A few areas of prominent spindle cell proliferation were identified, accompanied by a marked inflammatory cell infiltration (Figure 3d).
PMC9053012_03
H&E morphology of Case 2 (a), 3 (b), 4 (c), and 5 (d) shows similar histology to that seen in Case 1, except more confluent spindle cells in Case 5 (d); x200 original magnification. H&E, hematoxylin and eosin
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A few areas of prominent spindle cell proliferation were identified, accompanied by a marked inflammatory cell infiltration (Figure 3d).
PMC9053012_04
H&E morphology of Case 2 (a), 3 (b), 4 (c), and 5 (d) shows similar histology to that seen in Case 1, except more confluent spindle cells in Case 5 (d); x200 original magnification. H&E, hematoxylin and eosin
PUL2-12-e12004-g001.jpg
PMC9053012_05_PUL2-12-e12004-g001.jpg
pul212004-fig-0003
A few areas of prominent spindle cell proliferation were identified, accompanied by a marked inflammatory cell infiltration (Figure 3d).
PMC9053012_05
H&E morphology of Case 2 (a), 3 (b), 4 (c), and 5 (d) shows similar histology to that seen in Case 1, except more confluent spindle cells in Case 5 (d); x200 original magnification. H&E, hematoxylin and eosin
PUL2-12-e12004-g001.jpg
PMC9053012_05_PUL2-12-e12004-g001.jpg
pul212004-fig-0003
A few areas of prominent spindle cell proliferation were identified, accompanied by a marked inflammatory cell infiltration (Figure 3d).