[Primary mesenteric extraskeletal osteosarcoma: imaging findings]

We present a case of extraskeletal osteosarcoma arising from the root of the mesentery. This location is extremely rare; to our knowledge only three other cases have been reported. We describe the findings at computed tomography, positron emission tomography, and bone scintigraphy. We emphasize the radiologic differential diagnosis in this case, which was complicated by the presence of other malignant abdominal disease.