We describe a case of osteoid osteoma in the radial styloid of a 37-year old man mimicking de Quervain's disease. The exact diagnosis was made with CT examination and confirmed by histological evaluation of the tumour. The lesion was removed by curettage and symptoms were resolved rapidly thereafter. There was no sign of recurrence at one year follow-up.
Keywords: Osteoid osteoma; Radial styloid; de Quervain's disease.