title: Imaging-guided biopsy of (18)F-FDG-avid extrapulmonary lesions: do lesion location and morphologic features on CT affect the positive predictive value for malignancy?
abstract: OBJECTIVE
  The purpose of our study was to analyze the effect of lesion location and morphologic appearance on CT on the positive predictive value (PPV) for malignancy of all extrapulmonary lesions that were (18)F-FDG avid on PET/CT and that were biopsied under imaging guidance.
  
  
  METHODS
  Between January 2004 and December 2010, 227 patients underwent imaging-guided biopsy of 231 PET-positive extrapulmonary lesions with diagnostic pathologic results. The PET PPV for malignancy was retrospectively calculated and stratified according to lesion location and morphologic appearance.
  
  
  RESULTS
  The overall PET PPV for malignancy was 72%. Inflammatory processes accounted for the majority of benign biopsy results. Lesion location significantly affected the PPV (p < 0.001). Bone (96%) and liver (90%) lesions had significantly higher PPVs for malignancy compared with other locations, whereas lymph nodes (60%) had a significantly lower PPV for malignancy. Lesions that were morphologically suspicious and morphologically benign according to CT findings alone were associated with PPVs of 74% and 57%, respectively (p = 0.05). FDG-avid subcentimeter lymph nodes (n = 8) had a PPV for malignancy of 38%.
  
  
  CONCLUSIONS
  Over half of PET-avid morphologically benign-appearing lesions and one third of PET-avid subcentimeter lymph nodes were found to be malignant at biopsy, suggesting that benign morphologic appearance alone should not preclude further workup of a PET-positive lesion. Biopsies of FDG-avid lesions in liver and bone yielded high rates of true malignancy, whereas biopsies of lymph nodes yielded a lower rate of malignancy compared with other lesion locations.
authors.affiliation: Harvard Medical School, Peabody Society, 260 Longwood Ave, Boston, MA 02115, USA. mylinhnguyen@post.harvard.edu
authors.forename: My-Linh
authors.initials: ML
authors.lastname: Nguyen
authors.forename: Debra A
authors.initials: DA
authors.lastname: Gervais
authors.forename: Michael A
authors.initials: MA
authors.lastname: Blake
authors.forename: Peter R
authors.initials: PR
authors.lastname: Mueller
authors.forename: Dushyant V
authors.initials: DV
authors.lastname: Sahani
authors.forename: Peter F
authors.initials: PF
authors.lastname: Hahn
authors.forename: Raul N
authors.initials: RN
authors.lastname: Uppot
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D016009:Chi-Square Distribution; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D015641:Radiography, Interventional; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18