From the Radiologic Pathology Archives: Ewing Sarcoma Family of Tumors: Radiologic-Pathologic Correlation

Abstract

The Ewing sarcoma family of tumors includes osseous Ewing sarcoma, extraskeletal Ewing sarcoma, primitive neuroectodermal tumor, and Askin tumor. They share a karyotype abnormality with translocation involving chromosomes 11 and 22. Histologically, these lesions demonstrate crowded sheets of small round blue cells. Imaging features of osseous Ewing sarcoma often suggest the diagnosis, with aggressive long-bone destruction in the metadiaphysis of an adolescent or young adult and an associated soft-tissue mass. Focal areas of cortical destruction are frequent, allowing continuity between the intraosseous and extraosseous components. This continuity is also commonly seen as subtle channels extending through the cortex at computed tomography or magnetic resonance (MR) imaging, a finding that reflects the underlying pathologic appearance. Extraskeletal Ewing sarcoma commonly demonstrates a nonspecific radiologic appearance of a large soft-tissue mass affecting the paraspinal region or lower extremity. Askin tumor represents extraskeletal Ewing sarcoma involving the chest wall. Imaging typically reveals a large pleural-based mass and associated pleural effusion. Treatment of these tumors is usually a combination of neoadjuvant chemotherapy followed by surgical resection, which may be supplemented with radiation therapy. Imaging, particularly MR, is also vital to evaluate response to neoadjuvant therapy, direct surgical resection, and detect local recurrence or metastatic disease.

Multimodality imaging features, metastatic pattern and clinical outcome in adult extraskeletal Ewing sarcoma: experience in 26 patients

“…0.05). Compared with the skeletal muscle, tumours were isodense on CT (21/21), hypointense (n 5 5) to isointense (n 5 14) on T 1 weighted image, hyperintense on T 2 weighted image (19/19) and were fluorine-18 fludeoxyglucose ( 18 F-FDG)-avid [10/10; mean maximum standardized uptake value of 7 (range, [3][4][5][6][7][8][9][10][11]]. Necrosis (15/26), haemorrhage (5/26) and adjacent organ invasion (14/26) were present without calcification.…”

“…3 The terms peripheral primitive neuroectodermal tumour (PNET) and Askin tumour (thoracopulmonary PNET) are no longer used; these tumours are identical to EES. 4 Data from the Surveillance, Epidemiology and End Results (SEER) report an overall incidence of one case of EES per 1 million in the USA. 5 In the UK, EES is the second most common sarcoma accounting for 39% of childhood bone sarcomas with an estimated incidence of 1.58-2.21 per million person years.…”

Case 2: a 10-year-old girl with hip pain

“…5). Of these lesions, an initial such appearance is most typical of Ewing sarcoma, which is usually permeative rather than frankly lytic and often contains areas of sclerosis (due to necrotic and reactive bone) and unusual bony remodeling [2,3]. Osteosarcoma and lymphoma might also be considered for aggressive pediatric bone lesions with sclerosis [4].…”

“…skull, scapula, pelvis, rib, sternum) lesions include Ewing sarcoma and Langerhans cell histiocytosis, which each affect flat bones in up to 40-50% of cases [2,5,6], though Langerhans cell histiocytosis occurs much more commonly in the calvarium than Ewing sarcoma. However, flat bones may be affected by just about any process.…”

“…Osteomyelitis and trauma are common throughout childhood and should be kept in mind as possibilities for most pediatric bone lesions. Up to 95% of Ewing sarcoma cases present between 4 and 25 years of age, most frequently from 10 to 15 years [2], and most localized cases of Langerhans cell histiocytosis occur from 5 to 15 years of age [9]. Neuroblastoma metastases can give aggressive bone lesions with soft-tissue masses, but 10 years of age is beyond the typical range.…”