[Unusual imaging findings of Ewing sarcoma in the childhood]

To review the cases of Ewing's sarcoma (ES) diagnosed in children at our hospital from 1995 to 2005 and to analyze uncommon imaging signs at diagnosis or during the course of the disease.

We reviewed the cases of 21 patients with ES (12 boys and 9 girls) diagnosed between the ages of 2 and 14 years. We analyzed the types of presentation, the imaging findings (plain-films, CT, and MRI), and the patients' evolution. All cases were confirmed at histological study.

The following uncommon manifestations were found in 11 patients: 2 vertebral, one cervical, and one dorsal ES that initially manifested as spinal cord compression and as a mediastinal mass, respectively; 2 sacral ES with ascending epidural masses; 1 mandibular ES; 1 costal ES with hemorrhagic cerebral metastases; 3 extraskeletal (thigh, buttocks, and pelvis minor) ES with bone metastases at diagnosis: the first two had spinal cord and nerve compression due to vertebral metastases; 2 ES had benign-appearing radiological findings (cortical lesion of the radius with osseous remodeling of the ulna and an expanding multilocular lesion of the fibula).

Although ES is the second most common malignant bone tumor in children, its unusual imaging findings are less well known. More than half (52.4 %) of our last 21 patients presented some of these manifestations at diagnosis or during follow-up, so radiologists should be aware of them and include ES in the prebiopsy diagnostic possibilities.