title: Mature posterior fossa teratoma mimicking dermoid cyst.
abstract: We describe a very rare case of mature posterior fossa teratoma in an adult who presented with clinico-radiological findings consistent with a dermoid cyst. A computed tomography scan showed a hypodense mass in the cistern magna with calcification and a sinus tract in the occipital bone. Magnetic resonance imaging revealed a hypo- to hyperintense mass without contrast enhancement. The intraoperative picture showed a dermal sinus and a cyst containing lipid, keratin and hair. Histopathological examination showed a tumor with components of all the three germ layers; thereby, a diagnosis of mature teratoma was made. The histopathological differentiation between teratoma and dermoid cyst is very valuable for ruling out the presence of immature/malignant or germinomatous components that would require further adjuvant therapies. Thus, we here present a rare case of posterior fossa teratoma mimicking dermoid cyst and emphasize the importance of histopathological differentiation between these entities.
authors.affiliation: Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan, bohara_manoj@hotmail.com.
authors.forename: Manoj
authors.initials: M
authors.lastname: Bohara
authors.forename: Hajime
authors.initials: H
authors.lastname: Yonezawa
authors.forename: Prasanna
authors.initials: P
authors.lastname: Karki
authors.forename: Yuriz
authors.initials: Y
authors.lastname: Bakhtiar
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hirano
authors.forename: Ikumi
authors.initials: I
authors.lastname: Kitazono
authors.forename: Nozomu
authors.initials: N
authors.lastname: Matsuyama
authors.forename: Kazunori
authors.initials: K
authors.lastname: Arita
mesh_terms: D000328:Adult; D003884:Dermoid Cyst / Q000175:diagnosis* / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D015192:Infratentorial Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D013724:Teratoma / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome