Objective: Adenomyoma is a rare benign non-neoplastic tumor-like lesion. It originates from abnormal embryonic buds but its pathogenesis has not been fully elucidated. Method: A 63-year old man with severe pain, intussusception and ileus underwent a resection of a part of the intestine containing a tumor mass acting as a lead point. Tissue was analysed using H&E, histochemical and immunohistochemical stains. Results: Lesion located in the mucosa, submucosa and muscularis propria consisted of glandular structures varying in size and morphology, the larger ones containing papillary projections and the smaller ones being similar to Brunner's and peribiliary glands, both of them surrounded by smooth muscle bundles. The lesion was not accompanied by ectopic pancreas, and it indicated a diagnosis of adenomyoma of the ileum. Glandular elements were CK7+ and CK20− and CDX-2−, opposite to intestinal mucosa. Conclusion: Adenomyoma is a mass lesion rarely found distal to the duodenum, which bares close clinical and morfological resemblance to a tumor and some non-neoplastic conditions. Cytokeratin expression favors the heterotopic pancreas theory of pathogenesis, but abnormal interaction between the endoderm-and mesoderm-derived tissues can not be excluded.