title: Metastatic type A thymoma: morphological and genetic correlation.
abstract: OBJECTIVE
  The vast majority of type A thymomas are diagnosed in tumour stages 1 or 2, and metastatic cases are exceedingly rare. The histological and genetic features of such metastatic type A thymomas have not been described in detail.
  
  
  RESULTS
  Five metastatic type A thymomas in tumour stage Masaoka IVb that had been reviewed by a panel of expert pathologists were analysed using comparative genomic hybridization (CGH). Cases 1, 2 and 3 showed the prototypical morphology of type A thymomas with mainly solid growth patterns. These cases displayed only very subtle nuclear irregularities and slight nuclear crowding, but no other atypical features. Mitoses were absent. Cases 3 and 4, in contrast, had a distinctly atypical morphology. CGH revealed partially recurrent alterations in four cases (with and without atypical morphology), including gains on chromosome 1q (one case), 17q (two cases), chromosome 19 (three cases) and 22q (one case) and losses on chromosome 17p (two cases) and 22q (one case).
  
  
  CONCLUSIONS
  Rare metastatic type A thymomas, both with typical and 'atypical' histological features, show partially recurrent genomic alterations that differ from the much more frequent localized and indolent tumours. The fact that these alterations were recurring points to a link between clinical behaviour and molecular features. Our findings may have implications for the management and treatment of such tumours.
authors.affiliation: Institute of Pathology, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Bürger
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Inga-Marie
authors.initials: IM
authors.lastname: Schaefer
authors.affiliation: Institute of Pathology, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Küffer
authors.affiliation: Institute of Pathology, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Hanibal
authors.initials: H
authors.lastname: Bohnenberger
authors.affiliation: Institute of Pathology, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Reuter-Jessen
authors.affiliation: Department of Pathology, Queen Elizabeth Hospital, Hong Kong, SAR, China.
authors.forename: John Kwok-Cheung
authors.initials: JK
authors.lastname: Chan
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Emmert
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Hinterthaner
authors.affiliation: Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Marx
authors.affiliation: Institute of Pathology, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Ströbel
mesh_terms: D000368:Aged; D002869:Chromosome Aberrations; D055028:Comparative Genomic Hybridization; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D013945:Thymoma / Q000235:genetics* / Q000473:pathology*; D013953:Thymus Neoplasms / Q000235:genetics* / Q000473:pathology*
keywords: atypical; comparative genomic hybridization; type A thymoma