PMC8006332_01
The excised left atrial appendage revealed few epicardial veins involved by a non-occlusive acute thrombotic angiopathy (A-C, with stars indicating veins at lower power magnification). The acute thrombotic angiopathy was characterized by eccentric intimal edema, endotheliosis (note swollen nature of endothelial cells adjacent to fibrin), and fibrin deposition (D). The vessels involved were determined to be veins based upon morphologic features including an attenuated smooth muscle layer and lined by endothelial cells that by immunoperoxidase staining expressed CD34 (E) and ERG (F) and were negative for D2-40 (G). Fibrin material associated with the endothelial injury was characteristically fuchsinophilic by Masson trichrome stain (H inset) and bright red by Russell-Movat pentachrome stain (I). The usually encountered findings of endocardial fibroelastosis (A) and cardiomyocyte hypertrophy (B,C) were also evident. Images (A-D) are from paraffin sections stained with hematoxylin and eosin. Original magnification for (A) at x20; for (B,C), and (E-I) at x100; for (D) at x400; and for (H inset) at x200.
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F1
Microscopic examination revealed the common findings of cardiomyocyte hypertrophy and endocardial fibroelastosis and also showed few epicardial veins with evidence of an acute thrombotic angiopathy characterized by intimal edema, endotheliosis, and overlying fibrin (Figure 1).
A ventilation and perfusion lung scan was performed. Analysis of the perfusion images revealed multiple mismatched segmental/subsegmental defects (particularly in the right lung) and matched non-segmental defects along the periphery of both lungs (A). Analysis of the ventilation images revealed moderate heterogeneity of tracer deposition with retention of radiotracer in the central bronchi and several areas of diminished ventilation along the periphery of both lungs (B). Both images are of the anterior view.
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F2
A ventilation and perfusion lung scan was performed and revealed findings consistent with acute pulmonary embolism (Figure 2).