Foveolar gastric metaplasia presenting as a duodenal tumor with an atypical appearance: a case report

BACKGROUND: Foveolar gastric metaplasia of the duodenum is a frequent but not as yet considered correlate of endoscopically detected duodenal polyps. The majority of foveolar gastric metaplasias associated with polyps presented a typical benign endoscopic appearance and they were diagnosed by biopsy. Here we report a case of a surgical-resected foveolar gastric metaplasia manifesting as a duodenal tumor with an atypical appearance. CASE PRESENTATION: An asymptomatic 56-year-old Asian man who presented with a foveolar gastric metaplasia of atypical appearance and had previously undergone esophagogastroduodenoscopy was referred to our hospital. A biopsy revealed a normal duodenum with an inflamed mucosa. Narrow band imaging with magnifying endoscopy revealed normal microvessels with normal micromucosa, which indicated non-neoplasia. Endoscopic ultrasonography using a miniature probe system (20 MHz) revealed a hypoechoic mass with multiple anechoic lesions (16-mm diameter) located in the mucosal layer. The lesion was excised via laparotomy assisted by endoscopic techniques similar to endoscopic submucosal dissection. The pathology indicated foveolar gastric metaplasia. CONCLUSIONS: Foveolar gastric metaplasia can present as a duodenal tumor. We identified two important clinical issues. First, foveolar gastric metaplasia can present as a duodenal tumor with an atypical benign appearance. Second, both endoscopic ultrasonography and narrow band imaging are useful techniques to increase the diagnostic rate of this condition.