Gastric Adenocarcinoma of the Fundic Gland Type Treated by Endoscopic Mucosal Resection: A Case Report and Review of the Literature

Abstract

Gastric adenocarcinoma of the fundic gland type (GA-FG) is a rare entity that has only recently been described and defined. There is ongoing controversy regarding the malignant potential of this lesion. We report the case of a GA-FG in a 49-year-old Caucasian man who was referred to endoscopy for management of an incidentally found gastric polyp. Endoscopy showed a single polypoid lesion in the gastric fundus which was successfully removed with endoscopic resection. Grossly, the polyp measured 1.1 cm in greatest dimension. Microscopic examination showed irregularly branched neoplastic glands covered with a nonneoplastic foveolar epithelium. The continuity between the neoplastic glands and the fundic glands is clearly identified, indicating the tumor arose from the fundic glands. The tumor cells exhibited occasional oxyntic cytoplasm with enlarged atypical nuclei. The tumor invaded the submucosa with complete disruption of the muscularis mucosae and mild lymphocytic and fibroblastic stromal reaction. No necrosis, mitosis, or lymph-vascular invasion was identified. Although some authors have proposed reclassification of GA-FGs as oxyntic gland polyps/adenomas, in light of several reported cases with submucosal invasion as well as lymphatic invasion, we maintain that this neoplasm is best categorized as an extremely well-differentiated adenocarcinoma to reflect its invasive potential.

Gastric Adenocarcinoma of Fundic Gland Type with Aggressive Transformation and Lymph Node Metastasis: a Case Report

“…This case demonstrates that GA-FG has potential to progress to an aggressive cancer with LN metastasis. Although GA-FG frequently invades the submucosa, its progression is characteristically so slow that it is considered a low-grade malignancy [67891011]. There has been only 1 report of a GA-FG to date in which venous invasion was detected in a focus in the subserosa that seemed to be tubular adenocarcinoma without apparent fundic gland differentiation [12].…”

“…There has been only 1 report of a GA-FG to date in which venous invasion was detected in a focus in the subserosa that seemed to be tubular adenocarcinoma without apparent fundic gland differentiation [12]. Given that GA-FG rarely invades the muscular layer and has not previously been reported to metastasize, treatment has typically consisted of endoscopic resection [6789]. However, the detection of a LN metastasis in our patient demonstrates that GA-FG can become an aggressive cancer with metastatic potential.…”

“…Although GA-FG has distinct phenotypic characteristics, no specific treatment strategy has been established. As with conventional gastric cancers, most patients with GA-FG are considered at minimal risk of developing metastases and have been treated by endoscopic submucosal dissection, the remainder undergoing surgical resection and LN dissection [148910]. In our clinical practice, the treatment strategy is chosen according to JCGC criteria [5] and the Gastric Cancer Treatment Guideline (GCTG) [15] but also considers the characteristic slow growth of GA-FG.…”

“…These tumors are usually located in the upper third of the stomach and arise from the deep layer of the gastric mucosa [3]. According to most previous reports, GA-FG is of low-grade malignancy [248910]. It frequently invades the submucosa; however, invasion of the muscular or deeper layers is rare and lymph node (LN) involvement has not been reported.…”

Endoscopic and Pathological Characteristics of <b><i>Helicobacter pylori</i></b> Infection-Negative Early Gastric Cancer

“…Lesions of the fundic gland type may display the characteristics of chief cells, which secrete pepsinogen-I and gastric lipase and are generally located in deep areas of the mucosal layer because this type of gastric cancer is pepsinogen-I-or H + /K + ATPase-positive. Therefore, the fundic gland type seems to be mainly composed of cells resembling chief cells [27,34,35]. The MIB-1 index ranged 5-30%.…”