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.

Signet-ring cell carcinoma arising from a fundic gland polyp in the stomach

“…A female predominance in nonfamilial FGPs suggests that hormones play a role in the development of FGPs [9] . Some reports have described sporadic FGPs with low-grade or high-grade dysplasia [10,11] and adenocarcinoma [3,4,6] . There are no reports of gastric signet ring cell carcinoma arising from sporadic FGPs.…”

“…However, gastric FGPs, which are the most common lesions, have typically been considered benign lesions with no risk 18045 December 21, 2014|Volume 20|Issue 47| WJG|www.wjgnet.com of malignant transformation. Sporadic FGPs are the most common type of gastric polyps that are found during upper endoscopy [6] . The prevalence of FGPs appears to be increasing due to the increased use of upper endoscopy, increased use of acid suppressive medications, and decreased prevalence of H. pylori infection [2] .…”

“…Some reports have described sporadic FGPs containing low-grade or high-grade dysplasia [1,2] . Adenocarcinoma of the fundic gland was recently proposed as a new variant of gastric adenocarcinoma [3,4] . However, there are no reports of signet ring cell carcinoma arising from a sporadic FGP.…”

Endoscopic features of early stage gastric adenocarcinoma of fundic gland type (chief cell predominant type): a case report

“…Gastric adenocarcinoma of fundic gland type (chief cell predominant type) frequently develops in the upper part of the stomach in older patients [9] . Endoscopic finding of gastric adenocarcinoma of fundic gland (chief cell predominant) type may appear to be submucosal tumor-like (60%) or flat or depressed (40%); have a whitish hue (70%); dilated vessels with branching architecture on the surface (50%) with non-atrophic surrounding mucosa (90%) [15] .…”

“…A case of gastric adenocarcinoma with chief cell differentiation was first reported by Tsukamoto, et al in 2007 [8] . Ueyama, et al reported ten cases and proposed gastric adenocarcinoma of fundic gland (chief cell predominant type) as a new entity of gastric adenocarcinoma [9] . Gastric adenocarcinoma of fundic gland (chief cell predominant type) is defined as a neoplasm that mainly consists of highly differentiated columnar epithelial cells resembling the fundic gland cells, mainly chief cells, with nuclear atypia.…”