Pediatric Chest: A Review of the Must-know Diagnoses

Shreya Sood, MD; Julia Rissmiller, MD; Anastasia Hryhorczuk, MD


Appl Radiol. 2018;47(4):4-14. 

In This Article

Chest Wall

Ewing Sarcoma

Palpable chest wall masses and rib anomalies typically include benign diagnoses including fibrous dysplasia and chronic recurrent multifocal osteomyelitis. However, the most worrisome and common malignant tumor of the chest wall is Ewing sarcoma and related tumors, including primitive neuroectodermal tumor (PNET) and Askin tumor of the chest wall.[23,24]

Ewing sarcoma is most frequently encountered in the first 3 decades of life, peaking between 10–15 years of age, with slight male predilection. 95% of patients are of Caucasian descent.[25] A translocation on the long arms of chromosomes 11 and 22 (t11;22) is seen in up to 90% of these tumors.[24,26] Many also express CD99 in the tumor membrane.[27]

Chest radiography may demonstrate pleural involvement including fluid and/or direct tumor extension. Pulmonary parenchymal disease and enlarged mediastinal lymph nodes may also be seen. Similar to other aggressive osseous tumors, bony manifestations include permeative, moth eaten lucencies, a wide zone of transition and associated soft-tissue mass. Periosteal reaction may be lamellated or spiculated. Smaller intra-osseous sclerotic components can be seen in flat bones, including the ribs.

Cross-sectional imaging allows for the assessment of cortical destruction and aids in defining the extent of the soft tissue mass. The superior soft tissue contrast of MRI renders it ideal for evaluating Ewing sarcoma. On T1-weighted sequences, tumors tend to be homogeneous, of intermediate intensity while on T2-weighted sequences, tumors are homogenous with low-to-intermediate signal intensity. These signal characteristics are attributed to high cellularity of Ewing sarcomas. A heterogeneous appearance on MRI may reflect intratumoral hemorrhage and/or necrosis. When posterior ribs are involved, MRI of spine should also be performed to assess for tumor extension.