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.