title: Transmission electron microscopy of fine needle aspiration biopsies of metastases. Accuracy of both techniques as established by biopsy diagnoses.
abstract: OBJECTIVE
  To determine the accuracy of fine needle aspiration biopsy in establishing the primary on cytology and on cytologic and electron microscopy examinations using tissue biopsy as the gold standard.
  
  
  METHODS
  A retrospective study of 96 nonrandomly selected cases of metastases with an unknown primary was carried out. Tissue biopsy was performed subsequently for confirmation. Proper clinical correlation was part of the analysis.
  
  
  RESULTS
  The accuracy of cytology in identifying the tumor category (e.g., carcinoma, sarcoma) and tumor type (e.g., adenocarcinoma, leiomyosarcoma) was 76% and 78%, respectively, while that of electron microscopy was 95% and 91%, respectively. The primary site was correctly identified by cytology in 59% and by electron microscopy in 88% of cases, provided that clinical parameters were also considered.
  
  
  CONCLUSIONS
  Electron microscopy is an ancillary technique useful in increasing the accuracy of tumor classification of metastatic neoplasms identified by fine needle aspiration biopsy.
authors.affiliation: Department of Pathology, Universidad Nacional Federico Villareal.
authors.forename: Delia Jara
authors.initials: DJ
authors.lastname: Facundo
authors.forename: Guillermo
authors.initials: G
authors.lastname: Quinonez
authors.forename: Esther
authors.initials: E
authors.lastname: Ravinsky
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle / Q000379:methods*; D003593:Cytoplasm / Q000648:ultrastructure; D005260:Female; D006801:Humans; D008297:Male; D008854:Microscopy, Electron / Q000379:methods*; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000473:pathology*; D015203:Reproducibility of Results; D012189:Retrospective Studies