Osteoid osteoma and osteoblastoma. Current concepts and recent advances.

Osteoid osteomas are common lesions, constituting one-eighth of the benign bone tumors. Their size (less than 1.5 cm) and characteristic radiographic and clinical presentation are usually diagnostic. Response to salicylates is quite variable and not a reliable sign. Extremely high levels of prostaglandin metabolites have been found in osteoid osteomas and may explain the inflammatory features of the lesions. Preoperative localization with computed tomography (CT) scans and intraoperative confirmation of location and resection with radioscintigraphy have dramatically reduced the recurrence rate in the last 26 patients. Complete excision, even if accomplished by intralesional technique, is successful in eradicating the tumor. Osteoblastomas constitute 1% of bone tumors. Although their histology differs minimally from osteoid osteomas, they achieve a larger size and behave more aggressively. Commonly occurring in the spine, they require careful anatomic delineation with CT scans and myelography. Complete excision eliminates the lesion.