A Rare Case of Primary Extraosseous Osteosarcoma (EOS) of the thigh: A Case Report

Authors

  • Chiheb Louizi Department of Clinical and Interventional Radiology, University Medical Center Göttingen, Germany
  • Ali Seif Amir Hosseini Department of Clinical and Interventional Radiology, University Medical Center Göttingen, Germany
  • Günther Engel Department of Clinical and Interventional Radiology, University Medical Center Göttingen, Germany
  • Omar Al-Bourini Department of Clinical and Interventional Radiology, University Medical Center Göttingen, Germany

DOI:

https://doi.org/10.3941/jrcr.5528

Abstract

Background: Extraosseous osteosarcoma (EOO) is a rare mesenchymal malignancy, which produces osteoid, bone, or chondroid material and is located in the soft tissue without attachment to skeletal bones.
Case presentation: A 57-year-old male patient presented with extraosseous osteosarcoma located in the left rectus femoris muscle. The external magnetic resonance imaging revealed a large, irregular non-homogeneous contrast enhanced mass (largest diameter 9.5 cm). The final pathological diagnosis yielded extraosseous osteosarcoma. After interdisciplinary tumor board discussion, the following procedure was recommended: neoadjuvant systemic therapy with subsequent resection of the tumor and postoperative continuation of systemic therapy as well as discussion of adjuvant radiotherapy.
Conclusion: EOO should be treated as a soft tissue sarcoma with aggressive behavior and multimodality treatment should be actively sought to improve treatment outcome.

EOO in the left thigh. A (axial), B (coronal): Proton density sequence images without contrast demonstrate a 9.5 x 6.2 x 8.0 cm mass with mixed solid (yellow arrow) and liquid (blue arrow) components. C (axial), D (coronal): Contrast enhanced T1-weighted MRI images show inhomogeneous contrast uptake (yellow arrows).

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Published

2024-11-30

Issue

Vol. 18 No. 12 (2024)

Section

Musculoskeletal Radiology

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