Fig 1.
The grade of atypia of gastric tumors according to the World Health Organization (WHO) 2010 classification.
(A) Low-grade intraepithelial neoplasia (HE staining). The tumor ducts consisted of epithelial cells with mild to moderate nuclear atypia. Stratified nuclei and mitotic figures were inconspicuous. (B) High-grade intraepithelial neoplasia (HE staining). The tumor ducts consisted of epithelial cells with high-grade nuclear atypia associated with stratified nuclei and mitotic figures. (C) Intramucosal carcinoma (HE staining). The formation of irregular branching of small ducts and cribriform ducts was evident, with distinct invasion to the stroma of the lamina propria. (D) Intramucosal carcinoma (HE staining). Tumor cells with severe structural atypia show solid and cord-like proliferation, associated with distinct invasion to the stroma of the lamina propria.
Table 1.
Clinicopathological characteristics of lesions.
Fig 2.
Histologic images of tubular type belonging to intestinal-type.
(A) A hematoxylin and eosin (HE)-stained image. Many tumors were flat and had a tubular structure. (B) Mucin phenotype of tumor (MUC5AC). Among 91 lesions, scattered MUC5AC-positive cells were seen in 70 lesions (76.9%). (C) Mucin phenotype of tumor (MUC6). Same lesion as that shown above in B. Some tumor cells were positive for MUC6. Positivity for MUC6 was also seen in Brunner’s glands. (D) Immunohistochemical findings of tumor (CD10). Most tumor cells, excluding MUC5AC- and MUC6-positive cells, were positive for CD10.
Fig 3.
Histologic features of tubulovillous type belonging to intestinal-type.
(A) An HE-stained image, showing intermingling of villous and tubular structures, forming a protruding lesion. (B) Immunohistochemical findings of tumors (CD10), showing that all tumor cells were positive for CD10.
Fig 4.
Histologic images of foveolar type belonging to gastric-type.
(A) An HE-stained image, showing a protruding lesion consisting of gastric foveolar epithelial cells. (B) Mucin phenotype of tumor (MUC5AC). All tumor cells were positive for MUC5AC.
Fig 5.
Histologic characteristics of Pyloric Gland-type (PG) belonging to gastric-type.
(A) The surface layer of a tumor (HE staining), showing hyperplasia of small atypical ducts and dilated atypical ducts. (B) The surface layer of a tumor (MUC5AC antibody staining), showing the presence of MUC5AC-positive cells in the superficial layer of the tumor. (C) The surface layer of a tumor (MUC6 antibody staining), showing the presence of MUC6-positive cells in a large area, excluding the superficial layer of the tumor. (D) The deep region of a tumor (HE staining), showing hyperplasia of small atypical ducts. A region showing hyperplasia of clear cells with no atypia was found in the deepest part of the tumor. (E) A deep part of a tumor (MUC6 antibody staining), showing the presence of MUC6-positive cells in a large area extending from the atypical ducts to the region of clear-cell hyperplasia. (F) A magnified image of a tumor (HE staining), showing a distinctly protruding lesion. A region of tumor duct and mucous duct hyperplasia was found in the lamina propria. The muscularis mucosa was compressed and pushed down deeply.
Table 2.
Clinicopathological characteristics of tumors according to histologic type.
Table 3.
Immunohistochemical findings of tumors and fundic glands in normal mucosa.
Fig 6.
Differentiation of pyloric-gland type to fundic glands.
(A) HE-stained image, showing proliferation of atypical glands associated with mildly enlarged nuclei. (B) Differentiation into fundic glands (pepsinogen-1). Tumor glands are positive for pepsinogen-1. (C) Differentiation into fundic glands (H,K-ATPase). Similar to pepsinogen-1, H,K-ATPase-positive cells can be seen in tumor glands.