Gastric adenocarcinoma of the fundic gland type: clinicopathological features of eight patients treated with endoscopic submucosal dissection

Abstract

Background Gastric adenocarcinoma of the fundic gland type (GA-FG) has been added to the 2019 edition of the World Health Organization’s list of digestive system-associated cancers. This lesion differentiates toward the fundic gland and mostly involves chief cell-predominant differentiation with low-grade cytology. Clinicians and pathologists are still unaware of this rare disease; consequently, some cases are incorrectly diagnosed. This study aimed to investigate the clinicopathological features of GA-FG using retrospective analyses of endoscopic and pathological findings. Materials and methods Samples were collected from patients diagnosed with GA-FG. The clinical courses of all patients were monitored prospectively and reviewed retrospectively. Available clinical information, endoscopic features, pathological appearance, and follow-up data were assessed. Immunohistochemistry [mucin (MUC) 2, MUC5, MUC6, P53, CDX2, Ki67, SYN, CD56, CGA, β-catenin, and pepsinogen-I] was examined using Envision two-step method.Results Eight cases of endoscopic submucosal dissection (ESD) were obtained from our institution. Patient age ranged from 48-80 years (mean, 65 years). Some patients were on acid-suppressing medication. Most lesions were located in the upper third (n = 7) and one was in the middle third of the stomach. Six lesions were of the superficial flat type, whereas two were of the superficial elevated type. Narrow-band imaging using magnifying endoscopy showed irregular microvascular patterns (MVPs) in four cases and regular MVPs in the remaining cases. All lesions were primarily solitary and ~6 mm in diameter (largest, 12 mm). The main body of the tumors were localized in the mucosal layer, of which six cases invade into the submucosal layer. Well-formed glands of chief cells were predominant. Tumor cells were positive for pepsinogen-I, MUC6, SYN, and CD56. Lymphatic and vascular infiltration and metastatic and recurrent disease were not observed in any case.Conclusion GA-FG, a well-differentiated adenocarcinoma with mild atypia, can be completely removed using ESD, with a favorable prognosis in patients.

Endoscopic submucosal dissection for gastric adenocarcinoma of the fundic gland type (chief cell predominate type): Four years’ experience from a tertiary hospital

“…This may be due to various reasons, such as lack of awareness of this category, difficulty in recognition on routine histology with HE stain, and insufficient tissue on biopsy for pathological evaluation, as the tumorous tissue usually lays in the deep mucosal layer 1,16 . Differential diagnosis of GA‐FGs includes fundic gland polyps, neuroendocrine tumors, pyloric gland adenoma, oxyntic gland adenoma, and well‐differentiated GA, etc 16,17 . Immunohistochemistry is of great help for the differential diagnosis of GA‐FGs, namely, MUC5AC for foveolar cells, MUC6 for mucous neck cells or pyloric gland cells, MUC2 for goblet cells, CD10 for intestinal brush border cells, PG‐I for chief cells, and H + /K + ‐ATPase for parietal cells 1,16 …”