title: Papillomas and carcinomas of the choroid plexus: histological and immunohistochemical studies and comparison with normal fetal choroid plexus.
abstract: BACKGROUND
  Choroid plexus tumors are rare. Results on immunohistochemical features are scanty and controversial even regarding normal plexus.
  
  
  METHODS
  Thirteen cases of choroid plexus tumors and five samples of normal fetal choroid plexus were submitted to immunohistochemical study using a panel of epithelial, neuronal and stromal markers.
  
  
  CONCLUSIONS
  Relevant histological findings were presence of clear cells in 3/5 papillomas (PP) and 7/8 carcinomas (CA) and all 5 fetal plexuses; rhabdoid cells, desmoplasia and vascular proliferation were found respectively in 3, 4 and 5 cases out of 6 poorly differentiated CA and were absent in PP and well differentiated CA. Pancytokeratin AE1/AE3 was strongly positive in all 13 cases, even in the undifferentiated component of poorly differentiated CA, where reactivity was focal in 3 and diffuse in 3 cases. Low molecular weight cytokeratin (35betaH11) was not expressed in any of the 8 CA, but was present in all 5 PP. In 4 of 6 poorly differentiated CA there was reactivity for smooth muscle actin (1A4) in 10 to 30% of the cells. This was true also for one case lacking rhabdoid cells. Laminin was undetectable in all 6 cases of poorly differentiated CA but was present in 4 PP and 2 well differentiated CA. All 5 fetal plexuses expressed GFAP.
authors.affiliation: Department of Anatomic Pathology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Ana Silvia Carvalho de Menezes
authors.initials: AS
authors.lastname: Barreto
authors.forename: José
authors.initials: J
authors.lastname: Vassallo
authors.forename: Luciano de Souza
authors.initials: Lde S
authors.lastname: Queiroz
mesh_terms: D000293:Adolescent; D000328:Adult; D002277:Carcinoma / Q000196:embryology / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D002831:Choroid Plexus / Q000196:embryology / Q000473:pathology*; D016545:Choroid Plexus Neoplasms / Q000196:embryology / Q000473:pathology*; D005260:Female; D005910:Glioma / Q000196:embryology / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D020288:Papilloma, Choroid Plexus / Q000196:embryology / Q000473:pathology