title: Pulmonary meningothelial-like nodules: a genotypic comparison with meningiomas.
abstract: BACKGROUND
  Minute pulmonary meningothelial-like nodules (MPMNs) are incidental interstitial pulmonary nodules. They share histologic, ultrastructural, and immunohistochemical features with meningiomas (MGs).
  
  
  METHODS
  Sixteen cases yielding 33 separate MPMNs and 10 cases of benign MG were studied. Immunohistochemical studies and mutational analyses were performed on microdissected tissue using 20 polymorphic microsatellite markers targeting 11 genomic regions in an effort to identify genetic similarities of MPMN and MG.
  
  
  RESULTS
  A total of 96.6% of MPMNs stained positive for vimentin, 33.3% for epithelial membrane antigen, 3% for S-100, and all were negative for cytokeratin and synaptophysin. Loss of heterozygosity (LOH) was identified in 25% of single MPMN affecting 3 genomic loci. No solitary MPMN had more than 1 LOH event. Multiple LOHs were seen only in MPMN-omatosis syndrome, where 33.3% of MPMNs showed LOH affecting 7 genomic loci. MG showed the highest frequency of LOH with major events seen at 22q (60%), 14q (42.8%), and 1p (44.4%) that were not shared by MPMN.
  
  
  CONCLUSIONS
  Isolated MPMN lacks mutational damage, consistent with a reactive origin. MPMN-omatosis syndrome might represent the transition between a reactive and neoplastic proliferation. MPMNs are different from MG based on the major molecular genetic events seen in their formation and progression.
authors.affiliation: Department of Pathology, Division of Anatomic Pathology, University of Pittsburgh Medical Center, Presbyterian University Hospital, Room A610, 200 Lothrop St., Pittsburgh, PA 15213, USA. ionescudn@msx.upmc.edu
authors.forename: Diana N
authors.initials: DN
authors.lastname: Ionescu
authors.forename: Eizaburo
authors.initials: E
authors.lastname: Sasatomi
authors.forename: Dalal
authors.initials: D
authors.lastname: Aldeeb
authors.forename: Bennet I
authors.initials: BI
authors.lastname: Omalu
authors.forename: Sydney D
authors.initials: SD
authors.lastname: Finkelstein
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Swalsky
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Yousem
mesh_terms: D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D002883:Chromosomes, Human, Pair 14 / Q000235:genetics; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics; D004252:DNA Mutational Analysis; D005260:Female; D005838:Genotype; D006801:Humans; D007150:Immunohistochemistry; D019656:Loss of Heterozygosity; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008577:Meningeal Neoplasms / Q000235:genetics; D008579:Meningioma / Q000235:genetics* / Q000473:pathology* / Q000648:ultrastructure; D008875:Middle Aged; D010236:Paraganglioma, Extra-Adrenal / Q000235:genetics* / Q000473:pathology* / Q000648:ultrastructure