Trochlear nerve schwannoma with intratumoral hemorrhage: case report.
OBJECTIVE
Schwannomas originating from the trochlear nerve without neurofibromatosis are extremely rare. Thirty-four cases have previously been reported in the literature, and only 25 cases were pathologically diagnosed. In addition, intratumoral hemorrhage in intracranial schwannomas is also rare. Approximately 30 cases of intracranial schwannomas with intratumoral hemorrhage have been reported.


METHODS
A 42-year-old man presented with left hemiparesis and right trochlear nerve palsy. Magnetic resonance imaging revealed an abnormal cystic lesion beside the brainstem. His symptoms rapidly worsened after enlargement of the mass because of intratumoral hemorrhage.


METHODS
Gross total removal of the tumor was performed via the anterior transpetrosal approach. The tip of the trochlear nerve was fanned out and unified with the tumor. The tumor was diagnosed as a schwannoma.


CONCLUSIONS
The patient's hemiparesis improved postoperatively, and he was discharged 1 week after the operation. Magnetic resonance imaging performed 4 months later revealed no regrowth of the tumor. Only right trochlear nerve palsy has persisted. This report is the second case of intratumoral hemorrhage from a trochlear nerve schwannoma.
Department of Neurosurgery, Keio University School of Medicine, Tokyo, Japan. di045009@sc.itc.keio.ac.jp
Shigeo
S
Ohba
Tomoru
T
Miwa
Takeshi
T
Kawase
D000328:Adult; D002543:Cerebral Hemorrhage / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D003390:Cranial Nerve Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008297:Male; D009442:Neurilemmoma / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D020432:Trochlear Nerve Diseases / Q000150:complications / Q000175:diagnosis* / Q000601:surgery