PMC6013965_01
Histologic features of thrombotic microangiopathy in arteries. a Several submucosal arteries affected by acute TMA with surrounding perivascular hemorrhage (hematoxylin and eosin, original magnification x40). b Arteries with marked luminal narrowing due to accumulation of intimal fibrin with swelling overlying endothelial cells (hematoxylin and eosin, original magnification x400). c Artery with mark intimal edema. Scattered red cell are present within the artery intimal zone and adjacent perivascular stroma (hematoxylin and eosin, original magnification x400). d Occlusion of arterial lumina due to mucoid intimal edema in left artery and numerous red blood cell fragments with underlying fibrin in right artery (hematoxylin and eosin, original magnification x400)
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Fig1
A post-mortem analysis of the resection specimen revealed TMA involving numerous arteries and arterioles in the ileal and colonic submucosa as well as few thrombosed arterioles in the muscularis propria and deep lamina propria of the mucosa (Figs. 1 and 2).
Thrombotic microangiopathy in arterioles of resection specimen (a, b) and prior colonic mucosal biopsies (c, d). a Arterioles in muscularis propria with subendothelial fibrin. b Submucosal arterioles showing marked subendothelial edema with formation of concentric layers of new basement membrane material. c Capillaries/arterioles of deep lamina propria and superficial submucosa with intraluminal fibrin thrombi (arrows). Arteriole with subendothelial edema and new subendothelial basement membrane layer (arrowhead). d Superficial submucosal arteriole with subendothelial fibrin (arrow) and perivascular hemorrhage. (hematoxylin and eosin, original magnification x400 for a-d)
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PMC6013965_01_40164_2018_106_Fig2_HTML.jpg
Fig2
A post-mortem analysis of the resection specimen revealed TMA involving numerous arteries and arterioles in the ileal and colonic submucosa as well as few thrombosed arterioles in the muscularis propria and deep lamina propria of the mucosa (Figs. 1 and 2). In addition to the initially reported findings, biopsies from days 146 and 217 showed subtle features of TMA (Fig. 2); these included rare thrombosed arterioles in the deep lamina propria and superficial submucosa surrounded by perivascular hemorrhage as well as few arterioles with subendothelial expansion by pale material accompanied by underlying layers of new basement membrane material.