PMC4322293_01
PMC4322293_02
Histopathological findings of lung tissue section obtained from case 1 visualized by Elastica-Goldner staining. (a) Small pulmonary artery containing old thrombi. The lumen is separated into several channels by recanalization of organized thrombi. (b) Pulmonary vein with the recanalized thrombus separating the lumen into 3 channels. (c) Small pulmonary artery (200 mum in diameter) with moderate medial thickening and longitudinal smooth muscle proliferation inside the lumen (arrow). The thrombus is shown in the lumen (triangular arrow).
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fig1
Histopathology revealed long-term and extensive in situ thrombosis in the small pulmonary arteries (Figure 1(a)) and pulmonary veins (Figure 1(b)). Some small pulmonary arteries (>100 mum in diameter) showed luminal narrowing and occlusion by longitudinal smooth muscle (Figure 1(c)).
PMC4322293_03
Histopathological findings in small pulmonary arteries and pulmonary veins of case 2. (a) Peripheral small pulmonary artery with newly formed eccentric intimal fibrous proliferation considered to be a thrombus, because intimal lesions usually form concentric layers in plexogenic arteriopathy. (b) The peripheral small pulmonary artery (40 mum in diameter) shows complete occlusion by a thrombus. (c) Most small pulmonary veins are almost occluded by newly formed thrombi.
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fig2
Pathological findings revealed that small pulmonary arteries and veins (<30-50 mum in diameter) were almost completely occluded by newly formed thrombi not yet organized (Figures 2(a)-2(c)).
PMC4322293_04
Histopathological findings in small pulmonary arteries and pulmonary veins of case 3. (a) Almost all small pulmonary arteries have mildly thickened media and are occluded by thrombi. (b) Peripheral small pulmonary artery showing almost completely occluded by a newly formed thrombus. Most thrombi shown in small pulmonary arteries are in the process of being formed.
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fig3
However, thrombi at varying stages were found in almost all peripheral small-sized pulmonary arteries (Figure 3(a)). Most thrombi were still in the process of formation (Figure 3(b)).
PMC4322293_05
Histopathological findings in a small pulmonary artery of the right lung of case 4. This small pulmonary artery has moderate medial thickening and eccentric intimal fibrous proliferation (thrombus).
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fig4
Some small pulmonary arteries (<100 mum in diameter) and pulmonary veins showed intimal fibrous proliferation (Figure 4).