Ewing sarcoma - rib

Case contributed by Dr Brian Gilcrease-Garcia

Presentation

Several months of right chest pain.

Patient Data

Age: 11 years
X-ray

Mixed lytic/sclerotic lesion involving the right lateral 10th rib with associated soft tissue density surrounding the lesion.

Given patient's age, finding is most suspicious for a primary neoplasm, unlikely metastasis. Recommend CT for further evaluation.

CT

Mixed lytic/sclerotic lesion of right posterolateral 10th rib, with extensive aggressive-appearing periostitis, as well as a multilobulated soft tissue component. Mass displaces and involves both the right 10th intercostal artery, as well as more superior right 9th intercostal artery. Mild mass effect on adjacent lung, diaphragm, and liver.

No evidence of further lesions.

Findings are most suggestive of a primary bone malignancy, especially Ewing's sarcoma. Other sarcoma such as osteosarcoma, aggressive chondrosarcoma, or rhabdomyosarcoma are less likely due to location.

Nuclear medicine

Tc99-MDP bone scintigraphy study shows single focus of abnormal enhancement at right lateral 10th rib, corresponding to single known lesion. No additional suspicious osseous lesion.

Histopathology reports

Ultrasound-guided core biopsy: Ewing sarcoma

  • malignant round cell tumor consisting of nests of cells forming an anastomosing network of
    tumor cells. Extensive necrosis with acute inflammation. Features are consistent with Ewing sarcoma
  • follow-up immunostains show diffuse dot-pattern positivity for vimentin with rare CAM5.2 positive tumor cells. Diffuse membrane-cytoplasmic positivity for CD99. FISH and FLI-1 studies will be followed, but findings are those of Ewing sarcoma

 

Subsequent rib resection: Ewing sarcoma, post-treatment with 20% viable cells

  • external surface notable for a masslike lesion abutting chest wall measuring approximately 4.5 x 3.3 x 2.1 cm with an adjacent apparent fracture and rupture of the chest wall measuring 3 x 0.5 cm, though this may be an artifact of surgical manipulation
  • attached soft tissue along margins comprised of muscle and fat
  • sectioning reveals portions of extensive crumbling necrosis of the bone as well as extension of apparent dark gray necrotic areas of bone comprising approximately 30% of the total bone mass submitted

Case Discussion

Ewing sarcoma of the chest wall most commonly involves the ribs, and tend to present late in disease course due to indolent growth. Surgical resection for local control is generally preceded by neoadjuvant chemotherapy and/or radiotherapy even in non-metastatic disease in order improve odds of total resection and to reduce the risk of recurrence and subsequent metastasis 1,2.

Imaging findings in this case are typical of thoracic Ewing sarcoma.

This patient was found to have non-metastatic disease, AJCC tumor size >8 cm, T0, M0 is stage IB. There was incomplete response to chemotherapy. Due to positive margins on resection, this patient underwent additional adjuvant radiotherapy in addition to standard adjuvant chemotherapy.

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Case information

rID: 65212
Published: 29th Dec 2018
Last edited: 1st Jan 2019
Inclusion in quiz mode: Included
Institution: Mallinckrodt Institute of Radiology at Washington University

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