Musculoskeletal #37

What is the diagnosis?

The MRI revealed a subchondral bone lesion in the superomedial region of the left femoral head, accompanied by noticeable and extensive bone edema in the surrounding area. There is also a minor effusion in the left hip joint.

Differential diagnosis includes either an osteochondral injury or, more likely, osteoid osteoma.

CT confirms the typical features of osteoid osteoma such as subchondral lucency within an internal sclerotic focus and the presence of sclerosis in the surrounding region

Reference: Bhure U et al: Osteoid osteoma: multimodality imaging with focus on hybrid imaging. Eur J Nucl Med Mol Imaging. 46(4):1019-36, 2019