Joseph Junewick, MD FACR
over 7 years ago
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Ewing Sarcoma - Sacrum
Joseph Junewick, MD FACR
|Diagnostic Category: Neoplasia Malignant
|Created: over 7 years ago
|Updated: over 7 years ago
17 year old male with painful swelling.
MR – Axial T1, sagittal axial and coronal T2, and sagittal and axial post-gadolinium T1 images demonstrate s lobulated T2 and post-gadolinium hyperintense mass arising from the sacrum and coccyx with soft tissue component extending into the pelvis and sciatic notch.
Ewing sarcoma represents a spectrum of small round cell tumors including Ewing sarcoma of bone, extra-osseous Ewing sarcoma and peripheral primitive neuroectodermal tumors. Patients often present in the second decade of life with pain, swelling and/or fever. Ewing sarcoma is more common in males and rare in those of African descent. Distribution of Ewing sarcoma of bone is nearly equally distributed between the axial and appendicular skeleton. Peripheral primitive neuroectodermal tumor and extra-osseous Ewing sarcoma tend to occur in the spine, pelvis and chest regions.
Metastatic disease most commonly occurs by the hematogenous route with lung, bone, and bone marrow being the most common sites. Hepatic metastasis is unusual and lymphatic spread is rare. Like osteosarcoma, micrometastatic disease is present in most patients at the time of diagnosis. Approximately one-quarter of patients will have detectable metastatic disease at presentation.
Currently, no accepted staging system for Ewing sarcoma exists. Disease is defined as localized when, by imaging or clinical means, it has not extended beyond the primary site or regional lymph nodes. Further, localized disease is divided into groups based on complete excision (Group I), microscopic residual disease (Group II) and gross residual disease (Group III). Similar to rhabdomyosarcoma, treatment protocols are often stratified based on the presence or absence of metastatic disease (Group IV) and on size, location and extent of the primary lesion. Extra-osseous Ewing sarcoma is grouped similar to rhabdomyosarcoma based on the presence of residual disease after resection.
Intensive combination chemotherapy is the mainstay of treatment. It is effective in reducing the volume of the primary tumor and treatment of metastatic disease. Local control is ideally achieved with surgical resection and/or radiation therapy. The overall survival is nearly 70% at 5 years with an event-free survival of 50% at 10 years. Major prognostic factors at the time of diagnosis include tumor site (resectablity), tumor volume, and the presence of metastases at the time of diagnosis. Younger children have better event free survival than older children and adults. However, response to preoperative chemotherapy is the most important variable.
Franzius C, Daldrup-Link HE, Wagner-Bohn A, et al. FDG-PET for the Detection of Recurrences from Malignant Primary Bone Tumors: Comparison with Conventional Imaging. Ann Oncol (2002); 13:157-160.