Localization of osteoid osteomas--use of radionuclide scanning and autoimaging in identifying the nidus

Surgical excision of osteoid osteomas is curative, but intraoperative localization and pathologic identification in submitted fragments may be difficult. We used preoperative technetium-99m methylene diphosphonate injection and intraoperative probing to localize the nidus of three clinically suspected cases of osteoid osteoma. Then in the pathology department, fine grain specimen x-rays and specimen autoimaging on undeveloped film were utilized. In all cases, technetium radioactivity localized within the lesion. Although the nidus was identified by fine grain specimen x-rays in only one case, the subsequent histologically proved osteoid osteoma corresponded in all cases to the fragment with the most intense autoimaging. We conclude that isotope scanning is effective in localizing osteoid osteomas at surgery, and autoimaging is effective in identifying the nidus itself by the pathologist.