Ischemic osteonecrosis, multifocal (molar/bicuspid region; 53 y/o male with atypical facial neuralgia). Brown/black, multicystic area of mushy marrow necrosis is seen beneath cortex of first molar region.  Inferior alveolar nerve is surrounded by semitranslucent gray material (gelatinous marrow) and the bony canal is largely destroyed.  A linear cavitation is seen just above the inferior cortex.  Gray/brown area on the left margin is old NICO surgery site (cuspid area) with healed poorly with dense fibrous scar and scattered hemosiderin deposition.