title: Prominent EMA 'dots' in tumour-induced Bergmann gliosis.
abstract: OBJECTIVE
  To describe an unusual pattern of epithelial membrane antigen (EMA) immunoreactivity in highly proliferative human Bergmann glia.
  
  
  RESULTS
  An immunohistochemical study was performed of postmortem cerebellar tissue from 18 adult patients with cerebellar damage of various aetiologies and 15 biopsies of diverse adult and paediatric cerebellar tumours. We observed marked proliferation of Bergmann glia with unusual prominent dot-like cytoplasmic EMA immunoreactivity in a case with extensive leptomeningeal sarcomatosis. Similar staining was not observed in association with other types of cerebellar pathology, except for other neoplastic conditions, such as leptomeningeal carcinomatosis, adult medulloblastoma, and pilocytic astrocytoma in children. At an ultrastructural level, the index case showed prominent endoplasmic reticulum with some intermediate filaments and lipofuscin granules, but no structures related to cilia or microvilli were observed.
  
  
  CONCLUSIONS
  We consider that prominent EMA dots in Bergmann glia might represent excessive activation induced by an overlying leptomeningeal tumour that stimulates the expression of early developmental antigens. This observation suggests modulation of the glial phenotype when exposed to a neoplastic microenvironment that, in turn, might influence the regenerative potential of Bergmann glia.
authors.affiliation: Neurological Tissue Bank of the Biobanc, Hospital Clinic, Insitut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Ellen
authors.initials: E
authors.lastname: Gelpi
authors.forename: Josep A
authors.initials: JA
authors.lastname: Bombi
authors.forename: Elena
authors.initials: E
authors.lastname: Martinez-Saez
authors.forename: Luis
authors.initials: L
authors.lastname: Caral
authors.forename: Teresa
authors.initials: T
authors.lastname: Ribalta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001254:Astrocytoma / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D002528:Cerebellar Neoplasms / Q000378:metabolism* / Q000473:pathology*; D002531:Cerebellum / Q000378:metabolism / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D005260:Female; D005911:Gliosis / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D008577:Meningeal Neoplasms / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D018396:Mucin-1 / Q000378:metabolism*; D055815:Young Adult
chemical_list: C060192:MUC1 protein, human; D018396:Mucin-1
keywords: Bergmann glia; EMA; dots; immunohistochemistry; leptomeningeal sarcomatosis