title: Sonographic Detection of Extracapsular Extension in Papillary Thyroid Cancer.
abstract: OBJECTIVE
  To identify and evaluate sonographic features suggestive of extracapsular extension in papillary thyroid cancer.
  
  
  METHODS
  Three board-certified radiologists blinded to the final pathologic tumor stage reviewed sonograms of pathologically proven cases of papillary thyroid cancer for the presence of extracapsular extension. The radiologists evaluated the following features: capsular abutment, bulging of the normal thyroid contour, loss of the echogenic capsule, and vascularity extending beyond the capsule.
  
  
  RESULTS
  A total of 129 cases of pathologically proven thyroid cancer were identified. Of these, 51 were excluded because of lack of preoperative sonography, and 16 were excluded because of pathologic findings showing anaplastic carcinoma, follicular carcinoma, or microcarcinoma (<10 mm). The final analysis group consisted of 62 patients with papillary thyroid carcinoma, 16 of whom had pathologically proven extracapsular extension. The presence of capsular abutment had 100% sensitivity for detection of extracapsular extension. Conversely, lack of capsular abutment had a 100% negative predictive value (NPV) for excluding extracapsular extension. Contour bulging had 88% sensitivity for detection of extracapsular extension and when absent had an 87% NPV. Loss of the echogenic capsule was the best predictor of the presence of extracapsular extension, with an odds ratio of 10.23 (P = .034). This sonographic finding had 75% sensitivity, 65% specificity, and an 88% NPV. Vascularity beyond the capsule had 89% specificity but sensitivity of only 25%.
  
  
  CONCLUSIONS
  Sonographic features of capsular abutment, contour bulging, and loss of the echogenic thyroid capsule have excellent predictive value for excluding or detecting extracapsular extension and may help in biopsy selection, surgical planning, and treatment of patients with papillary thyroid cancer.
authors.affiliation: Department of Radiology, Stanford University Medical Center, Stanford, California USA (A.K., J.K.W., R.B.J., T.S.D.); VA Palo Alto Health Care System, Palo Alto, California USA (A.M.T.); and Department of Radiology, Duke University, Durham, North Carolina USA (B.N.P.). kamaya@stanford.edu.
authors.forename: Aya
authors.initials: A
authors.lastname: Kamaya
authors.affiliation: Department of Radiology, Stanford University Medical Center, Stanford, California USA (A.K., J.K.W., R.B.J., T.S.D.); VA Palo Alto Health Care System, Palo Alto, California USA (A.M.T.); and Department of Radiology, Duke University, Durham, North Carolina USA (B.N.P.).
authors.forename: Ali M
authors.initials: AM
authors.lastname: Tahvildari
authors.affiliation: Department of Radiology, Stanford University Medical Center, Stanford, California USA (A.K., J.K.W., R.B.J., T.S.D.); VA Palo Alto Health Care System, Palo Alto, California USA (A.M.T.); and Department of Radiology, Duke University, Durham, North Carolina USA (B.N.P.).
authors.forename: Bhavik N
authors.initials: BN
authors.lastname: Patel
authors.affiliation: Department of Radiology, Stanford University Medical Center, Stanford, California USA (A.K., J.K.W., R.B.J., T.S.D.); VA Palo Alto Health Care System, Palo Alto, California USA (A.M.T.); and Department of Radiology, Duke University, Durham, North Carolina USA (B.N.P.).
authors.forename: Juergen K
authors.initials: JK
authors.lastname: Willmann
authors.affiliation: Department of Radiology, Stanford University Medical Center, Stanford, California USA (A.K., J.K.W., R.B.J., T.S.D.); VA Palo Alto Health Care System, Palo Alto, California USA (A.M.T.); and Department of Radiology, Duke University, Durham, North Carolina USA (B.N.P.).
authors.forename: R Brooke
authors.initials: RB
authors.lastname: Jeffrey
authors.affiliation: Department of Radiology, Stanford University Medical Center, Stanford, California USA (A.K., J.K.W., R.B.J., T.S.D.); VA Palo Alto Health Care System, Palo Alto, California USA (A.M.T.); and Department of Radiology, Duke University, Durham, North Carolina USA (B.N.P.).
authors.forename: Terry S
authors.initials: TS
authors.lastname: Desser
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000000981:diagnostic imaging* / Q000473:pathology*; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D000077273:Thyroid Cancer, Papillary; D013961:Thyroid Gland / Q000000981:diagnostic imaging; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D014463:Ultrasonography / Q000379:methods*
keywords: capsular invasion; extracapsular extension; extrathyroidal extension; head and neck ultrasound; papillary thyroid cancer