Spectrum of appearance of hyperostosis frontalis interna on In-111 leukocyte scans

It is important to differentiate cerebral uptake of In-111 labeled leukocytes in abscess, metastasis, infarct, hemorrhage, subdural hematoma, and meningitis from marrow accumulation in hyperostosis frontalis interna, a relatively common benign disorder. The intensity of activity can vary from faint to minimal, moderate to intense, but the pattern of symmetrical frontal uptake sparing the midline is a consistent finding. As illustrated here, findings may be confirmed by bone scans and CT scans.