title: Gastric adenocarcinoma of fundic gland type (chief cell predominant type): proposal for a new entity of gastric adenocarcinoma.
abstract: Only a few cases of gastric adenocarcinoma of fundic gland type have been reported. Gastric adenocarcinoma with chief cell differentiation (GA-CCD) has been recently reported as a new variant of gastric adenocarcinoma. However, its clinicopathologic features are uncertain. To elucidate them, GA-CCDs exhibiting pepsinogen-I expression (10 lesions: Group A) and randomly selected gastric adenocarcinomas of differentiated type (111 lesions: Group B) were evaluated in this study. Cell differentiation by MUC2, MUC5AC, MUC6, CD10, pepsinogen-I, H+/K+-ATPase and chromogranin A, cell proliferation by Ki-67, and overexpression of p53 protein were evaluated immunohistochemically. In Group A, all GA-CCDs were located in the upper third of the stomach. Tumors were small, with the average maximum diameter ranging from 4 to 20 (average, 8.6) mm. Histologically, GA-CCDs were well-differentiated adenocarcinomas composed of pale gray-blue, basophilic columnar cells with mild nuclear atypia, resembling chief cells. Immunohistochemically, scattered positivity for H+/K+-ATPase was observed in addition to expression of pepsinogen-I and MUC6, indicating focal differentiation toward parietal cells. In Group B, pepsinogen-I was very focally expressed in 2 cases. As these 2 cases exhibited different clinicopathological and histologic features, they cannot be categorized as GA-CCD. Mild atypism, no lymphovascular invasion, low proliferative activity, no overexpression of p53, and no recurrence indicated less aggressiveness of GA-CCD. GA-CCD is rare, but it has distinct clinicopathological characteristics, especially in terms of tumor location, histologic features, phenotypic expression, and low-grade malignancy. We propose gastric adenocarcinoma of fundic gland type (chief cell predominant type) as a new entity of gastric adenocarcinoma.
authors.affiliation: Department of Human Pathology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Ueyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Yao
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nakashima
authors.forename: Katsuya
authors.initials: K
authors.lastname: Hirakawa
authors.forename: Yumi
authors.initials: Y
authors.lastname: Oshiro
authors.forename: Minako
authors.initials: M
authors.lastname: Hirahashi
authors.forename: Akinori
authors.initials: A
authors.lastname: Iwashita
authors.forename: Sumio
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D000230:Adenocarcinoma / Q000145:classification / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D019872:Chief Cells, Gastric / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005748:Gastric Fundus / Q000378:metabolism / Q000473:pathology*; D017506:H(+)-K(+)-Exchanging ATPase / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D020116:Pepsinogen A / Q000378:metabolism; D013274:Stomach Neoplasms / Q000145:classification / Q000378:metabolism / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D020116:Pepsinogen A; D017506:H(+)-K(+)-Exchanging ATPase