oncology
Ewing Sarcoma
advanced
6 min
28 marks
6 questions
Clinical Scenario
A 12-year-old boy presents with a 6-week history of left thigh pain and swelling. He has been febrile intermittently and appears unwell. His mother noticed the thigh swelling increasing. On examination, he is febrile (38.2°C), has a tender, warm swelling of the mid-thigh, and walks with a limp. Laboratory tests show elevated ESR (85), CRP (120), WCC (14), and LDH. X-ray shows a permeative lesion with periosteal reaction in the femoral diaphysis.
AP and lateral radiographs of the left femur in a 12-year-old showing features of Ewing sarcoma. There is a permeative lytic lesion of the femoral diaphysis with a lamellated (onion-skin) periosteal reaction. A large soft tissue mass is visible. The lesion is diaphyseal which is characteristic of Ewing sarcoma (vs metaphyseal for osteosarcoma). MRI shows extensive marrow involvement and soft tissue extension.
Image source: Open Access medical literature (NIH/PubMed Central) • CC-BY License
Questions
Question 1 (4 marks)
Describe the clinical and radiographic features of Ewing sarcoma.
Question 2 (5 marks)
What is the diagnostic workup including biopsy and molecular testing?
Question 3 (6 marks)
Describe the treatment protocol including chemotherapy and local control.
Question 4 (5 marks)
Compare and contrast Ewing sarcoma with osteosarcoma.
Question 5 (4 marks)
What are the prognostic factors and survival outcomes?
Question 6 (4 marks)
Discuss extra-skeletal Ewing sarcoma and related tumors.
Exam Day Cheat Sheet
Must Mention
- •Peak age 10-15, diaphyseal location
- •Onion-skin (lamellated) periosteal reaction
- •t(11;22) EWSR1-FLI1 fusion (85%)
- •Small round blue cells, CD99+
- •VDC/IE chemotherapy
- •Radiation-sensitive (unlike osteosarcoma)
Common Pitfalls
- •Wrong bone location
- •Missing translocation
- •Wrong chemo regimen
- •Not knowing radiation role
- •Confusing with osteomyelitis
- •Wrong survival rates