title: The percutaneous needle biopsy is safe and recommended in the diagnosis of musculoskeletal masses.
abstract: BACKGROUND
  The purpose of this study was to analyze the role of percutaneous core needle biopsy in the diagnosis of musculoskeletal sarcomas.
  
  
  METHODS
  One hundred eighty-five biopsy procedures were performed on 161 musculoskeletal tissue masses suspected of being a sarcoma in 155 patients who underwent subsequent tumor resection. A percutaneous core needle biopsy was performed on all masses either in the clinic or under radiologic guidance. If an adequate diagnosis could not be made on the basis of this biopsy specimen, an open incisional biopsy was performed.
  
  
  RESULTS
  One hundred seventy-three core needle biopsy procedures were performed: 90 without radiologic guidance, 55 computed tomography guided, and 28 fluoroscopically guided. Twelve open incisional biopsies were performed. Eighty-three sarcomas, 67 benign mesenchymal tumors, and 11 metastatic epithelial tumors were identified. Analysis of the data reveals that only 7.4% of the masses required open biopsy. In 88.2% of the masses, a single percutaneous biopsy procedure was adequate, and no additional biopsy was necessary. There was a 1.1% rate of complications; none caused a change in the patient's treatment plan. There was a 1.1% rate of major diagnostic errors, none of which ultimately impacted on the patient's outcome. There were no unnecessary amputations. Percutaneous needle biopsy showed a positive predictive value of 100%, a negative predictive value of 82%, a sensitivity of 81.8%, and a specificity of 100%. The accuracy of a single-needle biopsy procedure to identify benign versus malignant lesions, exact grade, and exact pathology was 92.4%, 88.6%, and 72.7%, respectively.
  
  
  CONCLUSIONS
  The percutaneous needle biopsy was found to be extremely effective and safe for the diagnosis of musculoskeletal masses. This method allowed 88% of patients with suspected sarcomas to undergo a single-needle biopsy procedure before the initiation of definitive treatment. Patients undergoing percutaneous needle biopsy had lower rates of major diagnostic errors and complications than previously described for open biopsy. Open biopsy offered limited additional information when preceded by a needle biopsy, given that these tumors were difficult to identify even after final resection.
authors.affiliation: Washington Cancer Institute, Washington, District of Columbia 20010, USA. jimwelker@hotmail.com
authors.forename: J A
authors.initials: JA
authors.lastname: Welker
authors.forename: R M
authors.initials: RM
authors.lastname: Henshaw
authors.forename: J
authors.initials: J
authors.lastname: Jelinek
authors.forename: B M
authors.initials: BM
authors.lastname: Shmookler
authors.forename: M M
authors.initials: MM
authors.lastname: Malawer
mesh_terms: D001707:Biopsy, Needle / Q000295:instrumentation / Q000379:methods; D003581:Cytodiagnosis / Q000592:standards; D003937:Diagnosis, Differential; D006801:Humans; D009141:Musculoskeletal System / Q000473:pathology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012509:Sarcoma / Q000473:pathology*; D012680:Sensitivity and Specificity