title: Intraosseous Schwannoma of the Petrous Apex.
abstract: Background and Importance Intraosseous schwannoma is a relatively rare clinical entity that typically arises in vertebral and mandibular bone. Intraosseous schwannoma located entirely within the petrous bone is exceedingly rare, and only two cases have been reported to date. Clinical Presentation A 47-year-old Asian man was referred to our hospital with a chief complaint of double vision. Neurologic examination revealed left abducens nerve palsy. Radiologic imaging showed a 35-mm osteolytic expansive lesion located in the left petrous apex. We made a preoperative diagnosis of chondrosarcoma and performed surgical resection. Surgery was performed via a left subtemporal epidural approach with anterior petrosectomy. The histopathologic diagnosis of the tumor was schwannoma. Schwannoma arising from cranial nerves was excluded from intraoperative findings in conjunction with the results for cranial nerves, and intraosseous schwannoma was diagnosed. Postoperative course was uneventful, and abducens nerve palsy resolved immediately after surgery. Conclusion The differential diagnosis of intraosseous schwannoma should be considered for an osteolytic mass lesion within the petrous apex. Subcapsular tumor removal was considered ideal in terms of preservation of the cranial nerves and vessels around the tumor.
authors.affiliation: Department of Neurosurgery, Keio University hospital, Shinjuku-ku, Tokyo, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Tamura
authors.affiliation: Department of Neurosurgery, Keio University hospital, Shinjuku-ku, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Neurosurgery, Keio University hospital, Shinjuku-ku, Tokyo, Japan.
authors.forename: Maya
authors.initials: M
authors.lastname: Kohno
authors.affiliation: Department of Pathology, Keio University hospital, Shinjuku-ku, Tokyo, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Kameyama
authors.affiliation: Department of Diagnostic Radiology, Keio University hospital, Shinjuku-ku, Tokyo, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Fujiwara
authors.affiliation: Department of Neurosurgery, Keio University hospital, Shinjuku-ku, Tokyo, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yoshida
keywords: intraosseous; neurinoma; petrous apex; schwannoma