title: Demonstration of monoclonality in coexisting GH-producing adenoma and neuronal tissue.
abstract: BACKGROUND
  Pituitary adenoma and neuronal components may coexist in the sellar region, but discussion of the histogenesis of the neuronal component has been mainly based on the morphological similarity with the adenomatous component using immunohistochemical and ultrastructural methods. Neuronal differentiation within pituitary adenoma may be a metaplastic process, but no clear supporting evidence has been obtained. To investigate the monoclonality or polyclonality of the mixed lesion by the X-chromosome inactivation method.
  
  
  METHODS
  Tumor specimens from a 55-year-old acromegalic woman were subjected to histopathological study and clonal analysis. Histological examination found varying proportions of adenoma cells and neuronal component in the specimens. Light and electron microscopy revealed cells with transitional morphology between adenoma cells and neurons. However, the X-chromosome inactivation method demonstrated monoclonality of both adenoma and neuron-like cells.
  
  
  CONCLUSIONS
  Clonal analysis of the mixed lesion demonstrated that all tumor cells originated from a single cell.
authors.affiliation: Division of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan. ikeda@nsg.med.tohoku.ac.jp
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Ikeda
authors.forename: Wenbin
authors.initials: W
authors.lastname: Ma
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshimoto
mesh_terms: D000236:Adenoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D041321:Chromosomes, Human, X / Q000235:genetics*; D005260:Female; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*
chemical_list: D019382:Human Growth Hormone