Osteoid osteoma

Case contributed by Dr Micheál Breen


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 apsect 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 promximal 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 reative 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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Case information

rID: 25971
Published: 19th Nov 2013
Last edited: 4th Jun 2020
Inclusion in quiz mode: Included