Imaging Features of Primary Tumors and Metastatic Patterns of the Extraskeletal Ewing Sarcoma Family of Tumors in Adults: A 17-Year Experience at a Single Institution

Abstract

Objective: To comprehensively analyze the spectrum of imaging features of the primary tumors and metastatic patterns of the Extraskeletal Ewing sarcoma family of tumors (EES) in adults.

Materials and methods: We performed a computerized search of our hospital's data-warehouse from 1996 to 2013 using codes for Ewing sarcoma and primitive neuroectodermal tumors as well as the demographic code for ≥ 18 years of age. We selected subjects who were histologically confirmed to have Ewing sarcoma of extraskeletal origin. Imaging features of the primary tumor and metastatic disease were evaluated for lesion location, size, enhancement pattern, necrosis, margin, and invasion of adjacent organs.

Results: Among the 70 patients (mean age, 35.8 ± 15.6 years; range, 18-67 years) included in our study, primary tumors of EES occurred in the soft tissue and extremities (n = 20), abdomen and pelvis (n = 18), thorax (n = 14), paravertebral space (n = 8), head and neck (n = 6), and an unknown primary site (n = 4). Most primary tumors manifested as large and bulky soft-tissue masses (mean size, 9.0 cm; range, 1.3-23.0 cm), frequently invading adjacent organs (45.6%) and showed heterogeneous enhancement (73.7%), a well-defined (66.7%) margin, and partial necrosis/cystic degeneration (81.9%). Notably, 29 patients had metastatic disease detected at their initial diagnosis. The most frequent site of metastasis was lymph nodes (75.9%), followed by bone (31.0%), lung (20.7%), abdominal solid organs (13.8%), peritoneum (13.8%), pleura (6.9%), and brain (3.4%).

Conclusion: Primary tumors of EES can occur anywhere and mostly manifest as large and bulky, soft-tissue masses. Lymph nodes are the most frequent metastasis sites.

Keywords: Computed tomography; Ewing sarcoma family of tumors; Extraskeletal Ewing sarcoma; Imaging.

Fig. 1. 53-year-old woman with primary renal extraskeletal Ewing sarcoma family of tumors.

A. Coronal contrast-enhanced computed tomography scan of abdomen reveals large, heterogeneous, enhancing right renal mass with prominent internal vascular structure. Central, non-enhancing portions represent central tumor necrosis (asterisk). B. Gross pathological image from radical left nephrectomy demonstrates large mass in lower pole of kidney. Cut-surface shows pinkish yellow mass with internal hemorrhage and cystic change.

Fig. 2. 29-year-old man with thoracic extraskeletal Ewing sarcoma family of tumors.

A. Coronal contrast-enhanced computed tomography (CT) scan of chest shows multiple, pleural-based, enhancing masses (arrows) with large amount of pleural effusion. B. Axial contrast-enhanced CT scan shows bulky mediastinal mass in azygoesophageal recess, compressing esophagus and inferior vena cava (curved arrows).

Fig. 3. 21-year-old man with paraspinal extraskeletal Ewing sarcoma family of tumors.

Sagittal T2-weighted, fat-saturated magnetic resonance imaging scan shows hyperintense, dumbbell-shaped, extradural tumor left of S1-3. Tumor was connected to extraspinal component through neural foramen (arrowheads).

Fig. 4. 19-year-old man with primary extraaxial brain extraskeletal Ewing sarcoma family of tumors.

A. Coronal T2-weighted magnetic resonance imaging (MRI) scan shows hyperintense, dural-based mass in right frontal region. B. Sagittal post-gadolinium T1-weighted MRI scan shows intense contrast enhancement.

Fig. 5. 28-year-old man with lymph-node metastasis from pelvic extraskeletal Ewing sarcoma family of tumors.

A. Axial contrast-enhanced computed tomography (CT) scan shows perirectal, soft-tissue mass (arrowheads) invading left wall of bladder (arrows), which was proven to be Ewing sarcoma on biopsy. B. Axial contrast-enhanced CT scan shows conglomerated retroperitoneal lymphadenopathy (arrows).