Diagnostic approach to a rare case of osteoid osteoma of the astragalus.

: A rare case of osteoid osteoma of the ankle of the left foot is discussed. Standard X-ray and MRI were negative. Triphasic bone scintigraphy followed by CT were performed. Combined clinical CT and scintigraphy findings were highly suggestive of osteoid osteoma. This diagnosis was confirmed on histology.