Background: Early gastric cancers with duodenal invasion are rare, and no previous case of multiple early gastric cancer, one invading the duodenal bulb, has been reported.
Case presentation: A 79-year-old woman was investigated for upper abdominal discomfort. Endoscopic examination revealed an irregular nodulated lesion in the antrum area, and a reddish aggregated-type semi-circumferential nodulated lesion extending from the prepyloric area to the duodenal bulb through the normal mucosa with the antrum lesion. Biopsy revealed a tubular adenoma for the antrum lesion and a well-differentiated tubular adenocarcinoma for the prepyloric lesion. Distal gastrectomy with sufficient duodenal resection was performed. Microscopically, the antrum lesion appeared as a papillary adenocarcinoma, and the prepyloric lesion as a mainly papillary adenocarcinoma which partially invaded the submucosa without any sequential elongation for endoscopic findings. The lesion extended into the duodenal bulb, and was 12 mm in length from the oral end of Brunner's gland's area and limited within the duodenal mucosa.
Conclusion: Here, we present an unusual case of multiple early gastric cancer, one of which invaded the duodenum with relative wide mucosal spreading. This case illustrates that even early stage cancers located in the gastric antrum, particularly in the prepyloric area can invade the duodenum directly.