S2920 Oxyntic Gland Adenoma of the Stomach; A Case Study of an Under-Reported Entity

Abstract

INTRODUCTION: Oxyntic gland adenoma (OGA), also known as gastric adenocarcinoma with chief cell predominance is a rare entity, with incidence and prevalence data unknown. Given its rarity, we present a case of OGA incidentally found on EGD in a patient with complaints of dyspepsia. CASE DESCRIPTION/METHODS: A 58-year-old female with a history of smoking presented to the GI clinic for colorectal cancer screening. On presentation, ROS was only notable for dyspepsia not related to food intake or exercise. Her physical exam was unremarkable. She was scheduled for both colonoscopy for cancer screening and EGD for evaluation of dyspepsia. Colonoscopy was negative for cancer. EGD showed a solitary papule in the gastric fundus (Figure 1). The papule was raised, pale/white in color, 4 mm in diameter, and had a highly vascularized base. The papule was completely excised with cold biopsy forceps. Pathological analysis was notable for a completely resected papule without evidence of intestinal metaplasia. Further analysis revealed that the papule was composed of fundic gland mucosa, with chief cells predominating and low-grade cytologic features consistent with an oxyntic gland adenoma (Figures 2 and 3). DISCUSSION: OGA is characterized as a benign, solitary, polypoid growth, usually located in the fundus and less often in the cardia of the stomach. Prior studies have explored the histological patterns of these polyps and have defined them as either chief cell predominant, or a mixture of chief and parietal cells. The nomenclature is disputed as multiple names have been proposed for a similar histological description including: chief cell hyperplasia, chief cell hamartoma, and oxyntic gland adenocarcinoma with chief cell predominance. The last is a misnomer as these polyps lack atypical features such as mucous gland cells or foveolar epithelium. Additionally, they do not invade through the submucosa, as seen in other carcinomas. As some pathologists and gastroenterologists are still unfamiliar with the clinical and histological presentation of OGA, we highlight this rare finding for further discussion of its proper nomenclature and a better understanding of etiology, incidence, and prevalence in the United States.Figure 1.: Endoscopic View of Polyp (Encompassed in Black Circle).Figure 2.: Full Slice of Polyp revealing Fundic Type Mucosa Containing Oxyntic Gland Adenoma.Figure 3.: 200x Zoomed view of Fundic Mucosa with Oxyntic Gland Adenoma (Black Arrow points to normal Oxyntic gland and White arrows point to Oxyntic gland with Chief cell predominance).