title: Radiologically atypical congenital posterior fossa dermoid cyst presenting late in life.
abstract: We report the case of a 74-year-old woman who presented with deterioration in gait, short-term memory loss and urinary incontinence. She had a past history of excision of a cervical dermal sinus tract at the age of 5 years. CT scan in 2004 revealed ventriculomegaly and an extremely hypodense ovoid structure lying in the midline low posterior fossa with calcification anteriorly. On MRI, the lesion was hypointense on T1-eighted and hyperintense on T2-weighted images, with incomplete suppression on fluid-attenuated inversion-recovery images and marked restriction on diffusion weighted images. Cerebrospinal fluid isotope study revealed non-communicating hydrocephalus. Posterior fossa crainectomy and removal of the lesion was undertaken. Pathological study revealed a dermoid cyst. Post-operatively, her hydrocephalus persisted and a ventriculo-atrial shunt was inserted with excellent functional recovery.
authors.affiliation: Department of Neurosurgery, Royal Melbourne Hospital, Parkville, Victoria, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Wallace
authors.forename: Brian
authors.initials: B
authors.lastname: Tress
authors.forename: Pei Fun
authors.initials: PF
authors.lastname: Kwan
mesh_terms: D000367:Age Factors; D000368:Aged; D002526:Cerebellar Diseases / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D002531:Cerebellum / Q000473:pathology / Q000503:physiopathology; D003388:Cranial Fossa, Posterior / Q000473:pathology* / Q000503:physiopathology; D003399:Craniotomy; D019299:Decompression, Surgical; D003884:Dermoid Cyst / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D020546:Fourth Ventricle / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology* / Q000473:pathology* / Q000503:physiopathology; D015192:Infratentorial Neoplasms / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D008279:Magnetic Resonance Imaging; D019635:Neurosurgical Procedures; D016136:Spina Bifida Occulta / Q000150:complications*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014549:Urinary Incontinence / Q000209:etiology / Q000503:physiopathology