PMC6745468_01
(a) Gross appearance of the gastric ulcer. In the gastric angulus, a 1.7 cm x 0.6 cm healing ulcer was observed. The arrow indicates the gastric ulcer. (b) Hematoxylin and eosin- (H&E-) stained figure of the gastric ulcer (x100). (c) H&E-stained figure of the granulation tissue of the healing stage of the gastric ulcer (x200). Eosinophilic infiltration is observed around capillaries without vasculitis. (d) Higher magnification (x400) of subfigure (c). H&E-stained figure of the submucosal layers of the stomach (x200) (e) and small intestine (x200) (f). Eosinophilic infiltration is observed without vasculitis. M: mucosal layer. Scale bars = 100 mum (b), 50 mum (c, e, and f), and 20 mum (d).
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In the gastric angulus, a 1.7 cm x 0.6 cm healing ulcer was observed (Figures 1(a) and 1(b)). Histological examination of the stomach revealed that infiltration of numerous eosinophils was observed in the granulation tissue of the ulcer (Figures 1(c) and 1(d)). In addition, mild to moderate eosinophilic infiltration was observed in the mucosal and submucosal layers of the stomach (Figure 1(e)) and small intestine (Figure 1(f)).
(a) Gross appearance of the pancreas. (b) Gross view of all sections of the pancreas. The arrows indicate hemorrhage spreading from the pancreatic body and tail to the retroperitoneal adipose tissue. (c) Gross view of a section of the pancreatic body. The arrow and arrowheads indicate the hemorrhage and fat necrosis, respectively. (d) Hematoxylin and eosin- (H&E-) stained figure of acute pancreatitis (x100). The arrow indicates necrotizing vasculitis of a small-sized artery. (e) H&E-stained figure of necrotizing vasculitis of a small-sized artery (x100). (f) Higher magnification (x400) of the adventitia of the small artery seen in subfigure (e). Infiltration by numerous eosinophilic cells is observed. (g) Elastica van Gieson-stained figure of a small-sized artery (x100). The arrowhead indicates the internal elastic lamina. The internal elastic lamina disappears in the upper part of the small-sized artery. (h) Masson's trichrome-stained figure of the small-sized artery (x100). Fibrinoid necrosis is accentuated by the red staining of Masson's trichrome stain. (i) Immunohistochemical staining indicates that the numerous infiltrating cells around the small-sized artery are CD163-positive histiocytes (x200). H and T in (subfigures a and b) indicate the head and tail of the pancreas, respectively. A: artery. Scale bars = 100 mum (d, e, g, and h), 20 mum (f), and 50 mum (i).
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Macroscopically, multiple hemorrhages and fat necrosis were observed in the pancreas (Figures 2(a)-2(c)). Multifocal acute pancreatitis was histologically detected and shown to be associated with necrotizing vasculitis of small-sized vessels with numerous eosinophilic infiltration (Figures 2(d)-2(f)). Elastica van Gieson (EVG) staining revealed that the vessels had internal elastic lamina, demonstrating that they were small-sized arteries (Figure 2(g)). The fibrinoid necrosis in the vascular wall was accentuated by the red staining of Masson's trichrome stain (Figure 2(h)). Immunohistochemical staining demonstrated that many CD163-positive histiocytes surrounded the injured small-sized arteries (Figure 2(i)).
Histology of the lungs and bone marrow. (a) Hematoxylin and eosin- (H&E-) stained figure of the lungs (x200). Goblet cell metaplasia of the epithelium (arrowheads) and eosinophilic infiltration (ellipse) in the airway wall. (b) Higher magnification (x400) of subfigure (a). Infiltration of eosinophilic cells is observed. (c) H&E-stained figure of the bone marrow (x400). Marked increased eosinophil number is observed. Scale bars = 50 mum (a) and 20 mum (b and c).
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In addition, goblet cell metaplasia of the airway epithelium was observed (Figures 3(a) and 3(b)). A bone marrow specimen demonstrated a hypercellular marrow with markedly increased eosinophil count, which made up around 20% of the total bone marrow cells (Figure 3(c)).