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. Clinical presentation: 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. Conclusion: 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.