Localized nonsuppurative encephalitis has not as yet been generally recognized by neurologists, neurosurgeons or otologists, yet it arises more frequently than the sporadic accounts of cases in the literature would lead one to expect and is of considerable clinical importance. Characteristically it presents the signs of an abscess, but no abscess is found on exploration of the brain, and the patient in most cases recovers.
Occasionally he dies and there is discovered at autopsy an area of hemorrhagic encephalitis without suppuration. The first case was described by Oppenheim1 in 1899, and since then others have been reported by Voss (F.);2 by Borries,3 who spoke neatly of "the syndrome of abscess without abscess," and by Adson,4 Symonds,5 Voss (O.)6 and others. In all the recorded cases, with 3 exceptions, the lesion has occurred in the temporal lobe as a result of infection in the ear,
ATKINSON M. LOCALIZED NONSUPPURATIVE ENCEPHALITIS ADJACENT TO A FOCUS OF INFECTION IN THE SKULL. Arch NeurPsych. 1939;41(3):556-564. doi:10.1001/archneurpsyc.1939.02270150130011