We are presenting the case of a 42-year-old ?male patient, who was hospitalized due to an acute small bowel obstruction caused by a tissue mass of the mesentery. The patient reported that he had a history of a testicular tumour. For therapy of intestinal obstruction as well as for diagnostic reasons we decided to perform ?an explorative laparotomy. On histopathological examination the immunohistological staining was positive for myeloperoxidase (MPO) and KP-1 (CD68). Staining was slightly positive for Bcl-2, CD117, CD34, but negative for CD3, CD4, CD5, CD8, CD20, CD30, CD79, Bcl-6 and S-100. This leads to the diagnosis of a myeloid sarcoma. After recovery from surgery and chemotherapy, allogenic bone marrow transplantation was performed. Most intestinal obstructions are caused by postoperative adhesions or hernias and only in rare cases caused by a myeloid sarcoma.