Introduction
Oxyntic gland neoplasms (OGNs) are uncommon gastric growths, primarily composed of cells resembling chief cells. The fifth edition of the World Health Organization (WHO) classification includes both oxyntic gland adenoma and gastric adenocarcinoma of fundic gland type in the OGN category. While OGNs are a relatively new disease entity with largely unknown incidence and prognosis, we previously reported an OGN incidence of 0.36% in 7488 patients at an outpatient clinic between 2017 and 2021. However, that study had a limited patient cohort. In Japan, OGNs are classified as a special type of cancer, and endoscopic treatment (endoscopic submucosal dissection [ESD] or endoscopic mucosal resection using a cap-fitted panendoscope [EMRC]) is generally recommended. Nevertheless, given reports of the low malignant potential of OGNs, we have followed patients who opted for observation with upper endoscopy and CT scans instead of pursuing endoscopic treatment.
Aims & Methods
This study aims to determine the true frequency of OGNs in a larger patient cohort and to investigate size changes or metastasis in OGNs managed with observation. We retrospectively reviewed all upper gastrointestinal endoscopies performed at a high-volume outpatient clinic from December 2017 to November 2024, identifying newly diagnosed OGN cases based on histological examination. Patient demographics, endoscopic and histopathological findings, and clinical courses are presented.
Results
During the study period, 10,110 patients underwent 25,480 procedures, with 118 patients diagnosed with a total of 153 OGNs, resulting in a point prevalence of 1.2% (118/10,110). Among the 153 OGN lesions, 3 were classified as gastric adenocarcinoma of fundic gland type (GA-FG-M). The prevalence of GA-FG-M was 0.03% (3/10,110). Thirty-five patients (30%) had multiple lesions (simultaneously or metachronously). Sixty-five patients (55%) had a history of H. pylori infection. Endoscopic treatment was performed in 65 lesions (12 via ESD, 53 via EMR-C), with 19 of these 65 lesions (29%) showing submucosal invasion (depth range: 10-950 µm). Of the 88 lesions, the tumor was endoscopically unidentifiable after biopsy in 37 cases, while 51 lesions remained identifiable but were observed. Throughout a median follow-up of 347 days (range: 26-2555 days), none of these 51 cases showed changes in size or morphology, and no metastasis was detected on CT.
Conclusion
Although the WHO classification indicates that the prevalence of OGNs is unknown, this large cohort study demonstrated an OGN incidence of 1.2% and a GA-FG-M prevalence of 0.03%. Furthermore, observation of biopsy-diagnosed OGNs revealed no changes in size or metastasis on CT, suggesting that OGNs may be slow-growing tumors that do not always require immediate treatment.
References
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[2] Ueyama H, Yao T, Nakashima Y, et al. Gastric adenocarcinoma of fundic gland type (chief cell predominant type): proposal for a new entity of gastric adenocarcinoma. Am J Surg Pathol. 2010, 34(5):609-619.
[3] Yao T, Vieth, M. Oxyntic gland adenoma. Digestive system tumours. In World Health Organization Classification of Tumours 5th edition (ed. WHO Classification of Tumours Editorial Board) 83–84, (International Agency for Research on Cancer, World Health Organization, 2019.
[4] Asahara, Hikari, et al. "Clinicopathological Features and the Prevalence of Oxyntic Gland
Neoplasm: A Single-center Retrospective Study." Internal Medicine (2023): 0552-22.
[5] Japanese Classification of Gastric Carcinoma (October 2017 [The 15th Edition]),
Japanese Gastric Cancer Association, p30, 36, Tokyo, Kanehara Shuppan.
Disclosure
No COI