title: Surgical and histological observations of trochlear neurinoma: case report.
abstract: A 47-year-old woman presented with an extremely rare case of trochlear nerve neurinoma manifesting as left hemiparesis. Magnetic resonance imaging demonstrated a cystic tumor, 4 cm in diameter, in the right ambient and cerebellopontine cisterns, compressing the midbrain and upper pons. The preoperative diagnosis was trigeminal neurinoma. However, the tumor was identified arising from the trochlear nerve, and was totally removed via the posterior transpetrosal approach. The histological diagnosis was neurinoma. The patient's hemiparesis improved postoperatively. Preoperative diagnosis of trochlear neurinoma must distinguish the neurological presentations of trochlear and trigeminal neurinomas and to analyze the microanatomy of the tumor and skull base structures on neuroimaging.
authors.affiliation: Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Misaki
authors.initials: M
authors.lastname: Kohama
authors.forename: Kensuke
authors.initials: K
authors.lastname: Murakami
authors.forename: Toshiki
authors.initials: T
authors.lastname: Endo
authors.forename: Mika
authors.initials: M
authors.lastname: Watanabe
authors.forename: Teiji
authors.initials: T
authors.lastname: Tominaga
mesh_terms: D002524:Cerebellar Ataxia / Q000209:etiology; D003390:Cranial Nerve Neoplasms / Q000150:complications / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D004172:Diplopia / Q000209:etiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D009442:Neurilemmoma / Q000150:complications / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D010291:Paresis / Q000209:etiology; D020432:Trochlear Nerve Diseases / Q000150:complications / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*