Brodie's abscess

It sclerotic lesion is present in the distal femoral metaphysis anteriorly with a central area of lucency. The anterior cortex of the distal femoral metaphysis appears to be violated.

A central area of fluid like signal is present within the distal femoral metaphysis, with surrounding edema. The fluid signal extends through the anterior cortex the distal femoral metaphysis into the prefemoral fat. Moderately sized joint effusion is present.