PMC9931590_01
Endoscopic, and histopathological findings of the lesion. (A) Gastric endoscopy revealed a 2 cm x 3 cm irregular ulcerative tumor in the gastric angle. (B) The tumor appeared greyish white on the cut surface. (C) The lesion was composed of AC, SCC and GCLS components (HE, x10). (D) Well differentiated AC was arranged in tubular and lace-like (HE, x400). (E) SCC was arranged in nests with inconspicuous keratinization and intercellular bridges. A large number of lymphocytic infiltrations were observed in the stroma (HE, x400). (F) The GCLS was characterized by irregular sheets, ill-defined tubles or single cells accompanying with dense lymphocytic infiltration (HE, x400).
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F1
Gastric endoscopy revealed a 2 cm x 3 cm irregular ulcerative lesion in the gastric angle (Figure 1A), and biopsy of the lesion revealed adenocarcinoma. Macroscopically, the tumor appeared greyish white on the cut surface, with a maximum diameter of 4 cm, and invaded the serosa (Figure 1B). AC (accounting for approximately 20%) and GCLS (accounting for approximately 10%) (Figure 1C). AC was arranged in tubular and lace-like, mainly restricted within the mucosa and partly invaded into the submucosa (pT1b) (Figure 1D). SCC tumor cells were arranged in nests with inconspicuous keratinization and intercellular bridges (Figure 1E), and invaded into the serosa (pT4a). Tumor cells had weak eosinophilic cytoplasm and enlarged nuclei with prominent nucleoli and vesicular chromatin (Figure 1F).
Immunohistochemical and in situ hybridization findings of the lesion. AC and GCLS components were positive for (A) CDX2 (Envision, x200), (B) CK8/18 (Envision, x200) and (C) CEA (Envision, x200). SCC was positive for (D) P40 (Envision, x200), (E) P63 (Envision, x200) and (F) CK5/6 (Envision, x200). The glandular epithelium in (G) AC (x200) was EBER negative. The nuclei of neoplastic cells of (H) SCC (x200) and (I) GCLS (x200) were positive for EBER.
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F2
Immunohistochemically, AC and GCLS components were positive for CDX2, CK8/18 and CEA (Figures 2A-C), whereas SCC was diffusely positive for P40, P63 and CK5/6 (Figures 2D, E). AC was EBER negative (Figures 2G-I). Accordingly, the present case was diagnosed as GASC with EBV-positive component of SCC mixed with GCLS (pT4aN0).