title: Cerebellar desmoplastic medulloblastomas. A further immunohistochemical characterization of the reticulin-free pale islands.
abstract: We studied by immunohistochemistry the features of differentiation in 24 desmoplastic and 16 classic medulloblastomas (median patient ages, 18 and 6.5 years, respectively) with the use of a panel of cytoskeletal and synaptosomal markers. A distinctive pattern of immunoreactivity with a series of monoclonal antibodies (Mabs) was documented in the polar tumor cells forming the reticulin-free pale islands of the desmoplastic variant, denoting overt neuritogenesis. These comprised the following: (1) Mab Tp-NFP1A3 recognizing an epitope in the high-molecular-weight (Mr) isoform of neurofilament protein; (2) Mab AP18 to the high-Mr microtubule-associated protein 2; (3) Mab TUJ1 recognizing the class III beta-tubulin isotype (human h beta 4); and (4) Mab SY38 to synaptophysin. Immunoblot analysis confirmed the expression of h beta 4 in three medulloblastomas, yielding strong single bands in two desmoplastic medulloblastomas and a considerably weaker band in one classic medulloblastoma. Glial fibrillary acidic protein-positive tumor cells frequently formed an integral component of the pale islands. Oligodendrogliallike areas in one classic and in three desmoplastic medulloblastomas were immunopositive for the Mabs to synaptophysin, microtubule-associated protein 2, and h beta 4, indicating a neuroblastic nature. We propose that the reticulin-free structures of desmoplastic medulloblastomas constitute neoplastic foci with features of predominantly neuronal and, to a lesser degree, astroglial differentiation.
authors.affiliation: Department of Pathology, University of Virginia School of Medicine, Charlottesville 22908.
authors.forename: C D
authors.initials: CD
authors.lastname: Katsetos
authors.forename: M M
authors.initials: MM
authors.lastname: Herman
authors.forename: A
authors.initials: A
authors.lastname: Frankfurter
authors.forename: P
authors.initials: P
authors.lastname: Gass
authors.forename: V P
authors.initials: VP
authors.lastname: Collins
authors.forename: C C
authors.initials: CC
authors.lastname: Walker
authors.forename: S
authors.initials: S
authors.lastname: Rosemberg
authors.forename: R O
authors.initials: RO
authors.lastname: Barnard
authors.forename: L J
authors.initials: LJ
authors.lastname: Rubinstein
mesh_terms: D000293:Adolescent; D000328:Adult; D000911:Antibodies, Monoclonal; D001253:Astrocytes / Q000032:analysis / Q000473:pathology; D002135:Calcium-Binding Proteins / Q000032:analysis; D002528:Cerebellar Neoplasms / Q000032:analysis / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D008527:Medulloblastoma / Q000032:analysis / Q000473:pathology*; D008565:Membrane Proteins / Q000032:analysis; D009474:Neurons / Q000032:analysis / Q000473:pathology; D015675:Osteocalcin; D012155:Reticulin / Q000032:analysis*; D016708:Synaptophysin; D014404:Tubulin / Q000032:analysis
chemical_list: D000911:Antibodies, Monoclonal; D002135:Calcium-Binding Proteins; D008565:Membrane Proteins; D012155:Reticulin; D016708:Synaptophysin; D014404:Tubulin; D015675:Osteocalcin