PMC7290262_01
Representative images of the upper gastrointestinal examination and histopathological examination of the biopsied specimens. (a) A flat, elevated lesion 2 cm in diameter was found at the anterior wall of the middle part of the stomach. (b) Infiltration of numerous cells with abundant eosinophilic crystal structure and eccentric nuclei in the lamina propria. (c) CD79a expression in the infiltrating cells' cytoplasm. (d) IgA expression in the intracytoplasmic eosinophilic crystal structure.
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She complained of abdominal discomfort, and upper gastrointestinal endoscopy revealed a flat elevated lesion 2 cm in diameter at the anterior wall of the middle part of the stomach (Figure 1(a)). The microscopic observation of the specimen revealed the infiltration of numerous cells with abundant eosinophilic crystal structure and eccentric nuclei, infiltrating the lamina propria (Figure 1(b)). Immunohistochemically, the infiltrating cells showed CD79a expression and faint CD20 expression, and the intracytoplasmic eosinophilic crystal structure was positive for IgA (Figure 1(c) and (d)).
A representative image of the specimen resected by ESD and its histopathological findings. (a) A flat, elevated lesion 20 x 17 mm in diameter was observed. The yellow line is the cut line. (b) Mott cells were distributed mainly in the gastric mucosal layer and infiltrated the muscularis mucosae as well as slightly into the submucosal layer, with lymphocytic aggregate. Double arrows indicate the lesion area. (c) Abundant Mott cells were seen in the lamina propria without destruction of the glandular structure. (d) Mott cells formed a relatively clear boundary (yellow dotted line) with the surrounding gastric mucosa at the lateral side of the lesion. (e) In the submucosal layer, Mott cells infiltrated individually, in contrast to the mucosal layer.
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The resected specimen contained a 20 x 17 mm flat, elevated lesion (Figure 2(a)). A histopathological examination of the resected specimen revealed that the lesion was located mainly in the gastric mucosal layer and extended to the muscularis mucosae and slightly to the submucosal layer, with scattered lymphocytic aggregate without germinal centers (Figure 2(b)). Mott cells were abundantly observed in the lamina propria without the destruction of glandular structures (Figure 2(c)). Mott cells were more frequently observed in the lamina propria than in the muscularis mucosae or submucosal layer (Figure 2(d) and (e)).
In situ hybridization analyses showed no light chain restriction or EBER positivity ((a), (b), (c)). An immunohistochemical analysis with anti-H. pylori antibodies could not detect H. pylori (d).
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Mott cells showed CD79a expression with neither light chain restriction nor EBER positivity (Figure 3(a)-(c)). An immunohistochemical analysis with the anti-H. pylori antibodies (polyclonal, 1:50; Agilent, California, USA) could not reveal the existence of H. pylori, but all of the pathological findings were compatible with those of Russell body gastritis (Figure 3(d)).
(a) Representative images of the upper gastrointestinal examination 2 months after ESD. ESD scar (arrowhead), multiple new lesions (arrow). (b) A few Mott cells (arrow) were seen in the biopsy specimen taken from the new lesions.
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Upper gastrointestinal endoscopy performed 2 months after ESD revealed the presence of multiple new, flat, elevated lesions in the antrum up to about 1 cm in diameter, distant from the site of ESD (Figure 4(a)). Biopsy specimens were taken from the new lesions, and a histopathological examination revealed a few Mott cells in all of the biopsied specimens (Figure 4(b)).
(a) Representative images from the upper gastrointestinal examination at 1 year after eradication therapy. Multiple elevated lesions had almost disappeared. Arrowhead shows an ESD scar. (b) There were a few plasma cells, but no Mott cells in the biopsy specimen taken from the antrum wall of the stomach.
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At 1 year after eradication therapy, follow-up upper gastrointestinal endoscopy revealed that multiple lesions had almost disappeared, and the histological examination of a specimen from the antrum wall of the stomach found no Mott cells (Figure 5(a) and (b)).