29th April 2024

A 10-year-old boy presents with a two-week history of progressive pain and swelling in his right thigh.

A 10-year-old boy presents with a two-week history of progressive pain and swelling in his right thigh. His mother reports that he fell while playing soccer three weeks ago, but there were no obvious injuries at the time. On examination, the right thigh is swollen, warm, and tender to touch, particularly around the mid-shaft of the femur. He is reluctant to move the right leg due to pain.

Investigations:

C-reactive protein (CRP): elevated

Erythrocyte sedimentation rate (ESR): Elevated

X-ray of the right thigh: Lytic lesion in the femur with periosteal elevation

Which is the most likely diagnosis?