Intracranial trigeminal neuroma involving the infratemporal fossa: case report and review of the literature.

OBJECTIVE AND IMPORTANCE

Intracranial trigeminal neuroma extending extracranially is not a common finding. We report the case of a patient with a right cystic trigeminal neuroma arising in the middle temporal fossa and infratemporal areas. The clinical, radiological, and intraoperative features of these unusual lesions are discussed, and the relevant literature is reviewed.

CLINICAL PRESENTATION

A 35-year-old woman presented with a 4-year history of right serous otitis media associated with recent right facial paresthesia. A neurological examination revealed hypesthesia in the mandibular division of the right trigeminal nerve. Computed tomographic and magnetic resonance imaging scans demonstrated a 6 x 6 x 4-cm well-enhancing cystic mass arising from the middle temporal fossa and extending extracranially to the infratemporal fossa through the enlarged foramen ovale.

INTERVENTION

The tumor was extradural and originated from the right mandibular nerve. It was subtotally removed via a subtemporal-intradural and extradural approach. A pathological examination revealed a cystic neuroma. The patient has remained well during 12 months of follow-up, and no evidence of recurrence has been noted on magnetic resonance imaging studies.

CONCLUSION

Unilateral serous otitis media by obstruction of the eustachian tube is a rare initial manifestation of trigeminal neuroma. We emphasize the benefit of neuroradiological examinations (both computed tomographic scanning and magnetic resonance imaging), which provided the clearest preoperative localization of this large intra- and extracranial tumor. A combined frontotemporal and infratemporal fossa approach is preferred, considering the difficulty of surgical removal. The prognosis for most patients was good. Twenty-five previously reported cases were also reviewed.