There are only few papers describing extrauterine localisation of endometrial tumor sarcoma. Pathogenesis of this tumor is still not clear. Most of the authors suggest the heterotopic Mullerian ducts to be the origin of such tumors. We describe a case of 53 year old woman with endometrial tumor sarcoma localized in the mesenterium of the colon. Diagnostic problems and differential diagnosis is presented. The authors suggest to immunohistochemical methods (CK desmin) to facilitate diagnosis.