title: Schwannoma-like tumor in the anterior cranial fossa immunonegative for Leu7 but immunopositive for Schwann/2E.
abstract: Schwannoma arising from the olfactory system, often called olfactory groove schwannoma (OGS), is rare, as the olfactory bulb and tract, belonging to the central nervous system, should lack Schwann cells. Another rare entity called olfactory ensheathing cell tumor (OECT) has been reported, which mimics clinical and radiological characteristics of OGS. Here, we report two rare cases of schwannoma-like tumor in the anterior cranial fossa that showed negative staining for Leu7, but positive staining for Schwann/2E, and discuss their origin. Two cases of mass lesions in the anterior cranial fossa in a 26-year-old man and a 24-year-old woman were successfully removed. Morphological examination of these tumors was compatible with a diagnosis of schwannoma. Immunohistochemically, both cases were negative for Leu7, yielding a diagnosis of OECT, but were positive for the schwannoma-specific marker, Schwann/2E. Immunohistochemical staining results in our two cases question the current assumption that OGS and OECT can be distinguished only by Leu7 staining pattern. In conclusion, the origins of OGS and OECT remain to be determined, and further studies in larger numbers of cases are needed to characterize these rare tumors in the anterior cranial fossa.
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Christian Aïssè
authors.initials: CA
authors.lastname: Bohoun
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan.|Department of Neurosurgery, Hokkaido Ohno Memorial Hospital, Sapporo, Japan.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Terakawa
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Goto
authors.affiliation: Department of Diagnostic Pathology, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Diagnostic Pathology, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kuwae
authors.affiliation: Department of Diagnostic Pathology, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ohsawa
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Morisako
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Nakajo
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Sato
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ohata
authors.affiliation: Department of Human Pathology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yokoo
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology*; D018959:CD57 Antigens / Q000276:immunology*; D035262:Cranial Fossa, Anterior / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D009442:Neurilemmoma / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology*; D009830:Olfactory Bulb / Q000276:immunology / Q000473:pathology; D019292:Skull Base Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology*; D055815:Young Adult
chemical_list: D000911:Antibodies, Monoclonal; D018959:CD57 Antigens
keywords: Leu7; Schwann/2E; olfactory ensheathing cell tumor; olfactory groove schwannoma; tumor origin