Malignant potential in a Brunner's gland hamartoma.

Brunner's gland hamartomas are rare tumours of the duodenum. These lesions have previously been described as being benign, with no malignant potential. A case report is presented of a Brunner's gland hamartoma, whose histology revealed a focus of well marked epithelial dysplasia. This case suggests a dysplastic stage in the natural history of Brunner's gland hamartoma, and questions the malignant potential of these lesions.