Duodenal hamartoma - a case report and review of the literature

Brunner’s gland hamartoma is a rare benign tumor of the duodenum a single pedunculated polyp. Usually asymptomatic and discovered incidentally, these lesions may manifest as a cause of duodenal obstruction or upper gastrointestinal hemorrhage and require surgical excision. The aim of this study is to report a case of 46-year-old male patient presenting with abdominal discomfort. His past medical history was unremarkable. Fibrogastroduodenoscopy revealed a polyp of the duodenum sized 8 mm that was resected. Histological examination showed duodenal mucosa with hyperplasic villous structures and crypts with partial stomach epithelium, forming papillary proliferations. In the submucosa there were hyperplastic Brunner glands, some of them with cystic transformation, hyperplasia of tubules and villi lined by pseudostratified epithelium with reduction of the mucous secretion. Muscularis mucosae was with arborization of adipocytes. In the chorion there were a hyperplasia of smooth muscle cells and a lot of adipocytes. Immunostaining for MUC5 was positive in the metaplastic stomach epithelium while MUC2 was positively expressed only in the goblet cells. CD10 was positive in the apical part of the surface duodenal epithelium. Several case reports have described these lesion as non dysplastic and entirely benign. This case report shows that these lesions can become dysplastic.