Subperiosteal hematoma. Another scintigraphic "doughnut".

The "doughnut" sign has been described frequently in brain and skeletal scintigraphy, but not previously in a subperiosteal hematoma associated with neurofibromatosis and focal gigantism. The primary cause and evolution of this skeletal "doughnut" sign is discussed; a brief review of other causes of this scintigraphic finding also is given.