Isolated lympho-histiocytic inflammation of the Gasserian ganglion mimicking trigeminal schwannoma. 
We present an unusual case of a patient with trigeminal pain and hypesthesia suggesting trigeminal schwannoma, where histology demonstrated an inflammatory lesion of the Gasserian ganglion.  Patient history and imaging were typical for a trigeminal schwannoma with a dumbbell growth in the middle and posterior fossa.  Surgery was performed and resection of a firm mass intermingled with fascicles originating from the ganglion and the mandibular branch was carried out via a subtemporal approach.  Histological diagnosis revealed a non-caseating, vaguely granulomatous lymphocyte- and histiocyte-rich inflammation.  Inflammatory lesions of the Gasserian ganglion are rare but may mimic tumors.  Intraoperative biopsies should be taken prior to complete resection to limit neurological deterioration.