PMC6514522_01
a Esophagogastroduodenoscopy shows a superficial mucosal ulcerative lesion suspicious of type 0-IIc early gastric cancer in the anterior wall of the distal body of the stomach. b Abdominal computed tomography scan indicates no definite mass or wall thickening of the stomach and revealed neither lymph node enlargement nor distant metastasis. c Endoscopic submucosal dissection was performed.
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F1
Esophagogastroduodenoscopy revealed a mucosal erosive lesion with a well-visible underlying vascular pattern, suggestive of type 0-IIc early gastric cancer at the anterior wall of the distal body of the stomach (Fig. 1a). An abdominal computed tomography scan indicated no definite mass or wall thickening of the stomach and revealed neither lymph node enlargement nor distant metastasis (Fig. 1b). Subsequently, the patient underwent endoscopic submucosal dissection (ESD) and achieved en bloc resection with negative margins (Fig. 1c).
Representative histopathologic findings of endoscopic submucosal dissection specimen (HE). a Tubular moderately differentiated adenocarcinoma was observed (x100). b Squamous cell carcinoma (SqCC) with an intercellular bridge was found (x200). c, d Two individual carcinoma components invaded into the submucosal layer (x20). e Lymphovascular invasion was found (x400). f Few cells with mucin production were infrequently shown in the SqCC components (x400).
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F2
Adenocarcinoma components showed irregular glandular structures with a tubular type and were moderately differentiated (Fig. 2a). The SqCC components exhibited a large solid nest of squamous cells with intercellular bridges and keratinization (Fig. 2b). Both individual components had invaded into the submucosal layer (800 mum) (Fig. 2c, d) accompanied with extensive lymphoid follicles. Lymphovascular invasion was also found (Fig. 2e). Notably, a few cells with mucin production were infrequently found within some areas of the SqCC component (Fig. 2f).
Representative imaging of Immunohistochemistry (IHC). IHC for p40 was strongly expressed in squamous cell carcinoma (SqCC) components (a) but not in adenocarcinoma components (b). In contrast, CK7 showed no expression in SqCC components (c) and positivity in adenocarcinoma components (d). CEA was positively expressed in some areas of both SqCC (e) and adenocarcinoma components (f) (all x40).
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F3
As expected, immunohistochemistry (IHC) for p40 was positive in the SqCC components but negative in the adenocarcinoma components (Fig. 3a, b). IHC for CK7 was negative in the SqCC components but positive in the adenocarcinoma components (Fig. 3c, d). Interestingly, IHC for carcinoembryonic antigen (CEA) was positive in some areas of both components (Fig. 3e, f).