Duodenal leiomyosarcoma is a rare disease with poor prognoses for patients. The disease does not have a clear set of signs and symptoms that allows easy diagnosis. Diagnosis is made on the basis of histopathological identification of a mesenchymal lesion composed of malignant tumor cells and immunohistochemistry positive for smooth muscle actin, desmin, muscle specific actin, calponin and caldesmon. We report a case of a 56 year old woman with primary duodenal leiomyosarcoma which had metastasized to the pancreas and the celiac artery.