Increased localization of 99mTc-pyrophosphate in a bone island: case report.

A positive 99mTc-pyrophosphate bone scan is reported in a proven case of large compact bone island. Pyrophosphate uptake in this case is presumed to be due to either large size or growth of the bone island. A radionuclide bone scan does not always differentiate bone islands from metastatic or inflammatory sclerotic bone lesions.