title: FISH for MYC amplification and anti-MYC immunohistochemistry: useful diagnostic tools in the assessment of secondary angiosarcoma and atypical vascular proliferations.
abstract: BACKGROUND
  Secondary angiosarcoma and benign but microscopically atypical vascular proliferations (herein referred to as atypical vascular lesion or AVL) are rare consequences of radiation therapy and/or chronic lymphedema most commonly seen in breast cancer patients. Differentiating angiosarcoma from AVL can be difficult due to overlapping clinical and microscopic features. Recently, amplification of MYC has been associated with 55-100% of secondary angiosarcomas but is reportedly absent in AVL. We examined a series of secondary angiosarcoma and AVL for MYC amplification by fluorescence in situ hybridization (FISH) and expression by immunohistochemistry to investigate the diagnostic utility for discriminating angiosarcoma from AVL.
  
  
  METHODS
  Cases of secondary angiosarcoma (n = 8) and AVL (n = 4) were retrieved from our archives and examined by FISH and immunohistochemistry.
  
  
  RESULTS
  All angiosarcoma cases (8/8 = 100%) demonstrated high-level MYC amplification by FISH, whereas all AVLs (0/4 = 0%) were negative for MYC amplification. Additionally, all angiosarcoma cases (8/8 = 100%) demonstrated nuclear positivity for MYC, whereas all AVLs (0/4 = 0%) were negative.
  
  
  CONCLUSIONS
  Amplification of MYC and nuclear expression of MYC is present in secondary angiosarcoma but not AVL. These ancillary tests can be useful to distinguish angiosarcoma from AVL in difficult cases.
authors: Department of Dermatology, Cleveland Clinic Foundation, Cleveland, OH, USA.
authors: Anthony P
authors: AP
authors: Fernandez
authors: Yang
authors: Y
authors: Sun
authors: Raymond R
authors: RR
authors: Tubbs
authors: John R
authors: JR
authors: Goldblum
authors: Steven D
authors: SD
authors: Billings
mesh_terms: D000328:Adult; D000368:Aged; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005260:Female; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D006394:Hemangiosarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000556:secondary; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D014652:Vascular Diseases / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: C489427:MYC protein, human; D016271:Proto-Oncogene Proteins c-myc