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

Abstract

Objective: To describe the multimodality imaging features, metastatic pattern and clinical outcome in adult extraskeletal Ewing sarcoma (EES).

Methods: In this institutional review board-approved, health insurance portability and accountability act-compliant retrospective study, we included 26 patients (17 females and 9 males; mean age, 36 years; range, 18-85 years) with pathologically confirmed EES seen at our institute between 1999 and 2011, who had imaging of primary tumour. Imaging of primary tumour in all 26 patients and follow-up imaging in 23 was reviewed by two radiologists in consensus. Clinical data were extracted from electronic medical records.

Results: The most common primary sites were the torso (n = 13), extremities (n = 10) and head and neck (HN) region (n = 3). The mean tumour size was 9 cm (range, 3-22 cm); tumours of the torso were larger than those of other areas (p > 0.05). Compared with the skeletal muscle, tumours were isodense on CT (21/21), hypointense (n = 5) to isointense (n = 14) on T1 weighted image, hyperintense on T2 weighted image (19/19) and were fluorine-18 fludeoxyglucose ((18)F-FDG)-avid [10/10; mean maximum standardized uptake value of 7 (range, 3-11)]. Necrosis (15/26), haemorrhage (5/26) and adjacent organ invasion (14/26) were present without calcification. Median follow-up was 16 months. 5 patients had local recurrence (torso, 3; extremity, 1; and HN, 1). Metastases developed in 11 patients (torso, 7; extremities, 3; and HN, 1; p > 0.05); 8 at presentation, most commonly to lung (9/11), peritoneum (4/11), muscles (4/11) and lymph nodes (4/11). Nine patients (torso, 7; extremity, 1; and HN, 1) died (10 months median survival) (p > 0.05).

Conclusion: Adult EESs are large tumours, which frequently invade adjacent organs and metastasize to the lung. EESs of the torso are larger, have more frequent metastases and poorer outcomes.

Advances in knowledge: Adult EESs of the torso have poor outcomes compared with other EESs.

Figure 1.

A 24-year-old man with primary retroperitoneal (adrenal) extraskeletal Ewing sarcoma. (a, b) Axial and coronal reformatted contrast-enhanced CT images of the abdomen reveal a large heterogeneous enhancing right adrenal mass (white arrow) with contiguous tumour thrombus in the inferior vena cava (IVC) (white arrowheads) extending up to the right atrium (black arrowhead). The adjacent liver parenchyma is invaded at places. (c–e) Axial T₂ weighted, pre- and post-gadolinium fat-suppressed T₁ weighted MRI images demonstrate the mass to be heterogeneously hyperintense on T₂ weighted images and hypointense on T₁ weighted images (white arrows) with heterogeneous enhancement, haemorrhage in the form of T₁ hyperintense areas (black arrow) and enhancing tumour thrombus in the IVC (white arrowheads).

Figure 2.

A 63-year-old woman with extraskeletal Ewing sarcoma of the thigh. (a–c) Axial fat-suppressed T₂ weighted, pre- and post-gadolinium fat-suppressed T₁ weighted MRI images demonstrate a heterogeneously hyperintense mass on T₂ weighted images (arrows), which is heterogeneously isointense on T₁ weighted images with heterogeneous enhancement. (d) Coronal maximum intensity projection image of fluorine-18 fludeoxyglucose (¹⁸F-FDG) positron emission tomography/CT FDG uptake (maximum standardized uptake value of 12) in the right thigh mass (arrow) and multiple ¹⁸F-FDG-avid pulmonary metastases (arrowheads). (e) Axial CT image of the chest confirms the pulmonary metastases (arrow). (f). Haematoxylin and eosin staining (original magnification ×600) of the biopsy specimen of the tumour demonstrates sheets of uniform rounded cells with scant cytoplasm. (g). Fluorescence in situ hybridization analysis using break-apart probes directed against the 5′ and 3′ ends of the EWSR1 gene shows EWSR1 gene rearrangement.