title: The gonadotroph origin of null cell adenomas.
abstract: OBJECTIVE
  The term "null cell" adenoma was first proposed in 1980 to designate pituitary adenomas lacking clinical, biochemical and morphological markers to disclose their cell origin.
  
  
  METHODS
  The aim of this study was to investigate the presence of α- and β-gonadotropin subunits in clinically nonfunctioning pituitary tumors, which were initially immunonegative and thus diagnosed as null cell adenomas. For this reason, we reapplied immunohistochemistry using a more sensitive method comprising a tyramide signal amplification technique, combined with a polymer antibody immunohistochemical detection system.
  
  
  RESULTS
  With this approach, all these previously negative tumors became positive for α- and β-gonadotropin hormone subunits.
  
  
  CONCLUSIONS
  Our results prove that so-called "null cell" adenomas produce α-SU or/and β-FSH or β-LH and therefore are gonadotrph adenomas in origin.
authors.affiliation: Department of Pathology G. Gennimatas Athens General Hospital, Athens, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Kontogeorgos
authors.affiliation: Department of Pathology G. Gennimatas Athens General Hospital, Athens, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Thodou
mesh_terms: D000236:Adenoma / Q000737:chemistry* / Q000145:classification / Q000648:ultrastructure; D014408:Biomarkers, Tumor / Q000032:analysis*; D019070:Cell Lineage; D037201:Follicle Stimulating Hormone, beta Subunit / Q000032:analysis*; D015292:Glycoprotein Hormones, alpha Subunit / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D037101:Luteinizing Hormone, beta Subunit / Q000032:analysis*; D008854:Microscopy, Electron; D010641:Phenotype; D010911:Pituitary Neoplasms / Q000737:chemistry* / Q000145:classification / Q000648:ultrastructure; D009626:Terminology as Topic
chemical_list: D014408:Biomarkers, Tumor; D037201:Follicle Stimulating Hormone, beta Subunit; D015292:Glycoprotein Hormones, alpha Subunit; D037101:Luteinizing Hormone, beta Subunit