Myoepithelial hamartoma of the duodenum
Monday 08 June 2009, Branislav Kunčak, M. D.
Myoepithelial hamartoma is a developmental abnormality comprised of smooth muscle and epithelial structures that can be arranged in different ways. Only lesions where typical pancreatic acinar tissue is present are referred to as "ectopic pancreas". When there is an accumulation of smooth muscle and ductal structures, the term "myoepithelial hamartoma" is preferred.
Small bowel myoepithelial hamartomas are often located near the ampulla of vater, but can be found elsewhere in the small bowel. Also myoepithelial hamartoma of the stomach has been reported.
The usual gross appearance is that of a yellow, or yellow-white submucosal nodule, tumor or intramural mass with smooth surface. The lesions resemble lipomas.
Most cases are asymptomatic and diagnosed incidentally. Large lesions may cause biliary or pancreatic duct obstruction, GI bleeding or intussusception.
Malignant transformation of small bowel myoepithelial hamartomas is very rare.
» Jagmohan P et al. Myoepithelial hamartoma of the distal ileum - A rare cause of adult intussusception. Indian J Radiol Imaging 2006;16:185-8.
» Makhlouf HR et al. Carcinoma in jejunal pancreatic heterotopia.Arch Pathol Lab Med.1999 Aug;123(8):707-11.
»Portale TR et al. Myoepithelial hamartoma of the stomach simulating a gastric carcinoma. A case report.Tumori 2007;93:220-222.
Bigger image, Endoscopy
Fig. 1
Yellow-white tumor with smooth surface in the descending part of the duodenum. Biopsy from the lesion showed myoepithelial hamartoma fragments and fragments of normal duodenal mucosa.
