Osteoid osteoma

Case contributed by Micheál Anthony Breen
Diagnosis certain


Right upper thigh pain for 4 months.

Patient Data

Age: 3 years
Gender: Male

AP and frog-leg lateral radiographs of the pelvis show a cortical-based, 5mm ovoid lucency with tiny punctate internal calcifications and marked surrounding sclerosis and cortical thickening in the lateral aspect of the proximal right femoral diaphysis.


As noted on the prior radiographs, there is a focal, cortical lucent lesion along the lateral aspect of the proximal femoral diaphysis that measures 5mm in length. There is punctate calcification within this lesion. The lucent lesion is surrounded by robust cortical thickening and sclerosis.



Image from a DynaCT performed in the fluoroscopy suite showing the tip of a radiofrequency probe within the osteoid osteoma.

Case Discussion

Osteoid osteoma is a benign osseous tumor. They usually present in adolescents but can be seen in older patients and younger children as in this case. They are classically associated with significant night pain that is relieved by NSAIDs.

The appearance on radiographs and CT consists of a lucent nidus surrounded by reactive sclerosis. Central mineralization may be seen within the nidus. If the nidus measures over 2cm in length the lesion should be termed osteoblastoma.

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