Diagnostic value of endoscopic and endoscopic ultrasound characteristics of duodenal submucosal tumour-like heterotopic gastric mucosa.

Objective: Recent studies have reported that duodenal heterotopic gastric mucosa (HGM) has been observed in 8.9% of patients who undergo esophagogastroduodenoscopy. However, there are few reports concerning the endoscopic and endoscopic ultrasound characteristics of submucosal tumour-like HGM in the duodenum.
Methods: Endoscopic, endoscopic ultrasound (EUS) and histological findings were analyzed in six patients with submucosal tumour-like HGM, which were confirmed by pathological examination of biopsy or endoscopic polypectomy specimens.
Results: Endoscopically, the lesions appeared as a solitary, sessile submucosal tumour-like mass with a depression at the top. In four of six patients, small granular structures were found in the depressed area of the mass. On EUS, all masses demonstrated a heterogeneous pattern, among which four patients presented anechoic areas while two patients showed no anechoic areas. All lesions were localized within the mucosa and submucosa on EUS. Histologically, they consisted of gastric glands and some dilated glands, and were covered with normal duodenal epithelium. In four of six lesions, the tumours were composed of gastric-type foveolar epithelium showing papillary growth, fundic glands and pyloric glands, while the others consisted of gastric-type foveolar epithelium and pyloric glands.
Conclusion: A heterogeneous pattern on EUS and small granular structures on esophagogastroduodenoscopy represent valuable diagnostic features of submucosal tumour-like HGM.