title: The Validity of Ultrasonography-Guided Fine Needle Aspiration Biopsy in Thyroid Nodules 4 cm or Larger Depends on Ultrasonography Characteristics.
abstract: BACKGROUND
  The objective of this study was to evaluate the validity of fine needle aspiration biopsy (FNAB) according to ultrasonography (US) characteristics in thyroid nodules 4 cm and larger.
  
  
  METHODS
  We retrospectively reviewed the cases of 263 patients who underwent thyroid surgery for thyroid nodules larger than 4 cm between January 2001 and December 2010.
  
  
  RESULTS
  The sensitivity of US-FNAB was significantly higher in nodules with calcifications (micro- or macro-) than those without (97.9% vs. 87.% P<0.05). The accuracy of US-FNAB was higher in large thyroid nodules with US features suspicious of malignancy, such as a solid component, ill-defined margin, hypoechogenicity or marked hypoechogenicity, or any calcifications (micro- or macro-) compared to thyroid nodules with none of these features. Furthermore, the accuracy improved as the number of these features increased. The overall false negative rate (FNR) was 11.9%. The FNR of thyroid nodules that appeared benign on US, such as mixed nodules (7.7%) or nodules without calcification (9.8%), trended toward being lower than that of solid nodules (17.9%) or nodules with any microcalcification or macrocalcification (33.3%). In nodules without suspicious features of malignancy, the FNR of US-FNAB was 0% (0/15).
  
  
  CONCLUSIONS
  We suggest individualized strategies for large thyroid nodules according to US features. Patients with benign FNAB can be followed in the absence of any malignant features in US. However, if patients exhibit any suspicious features, potential false negative results of FNAB should be kept in mind and surgery may be considered.
authors.affiliation: Department of Endocrinology and Metabolism, Chosun University Hospital, Chosun University School of Medicine, Gwangju, Korea.
authors.forename: Jin Hwa
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Na Kyung
authors.initials: NK
authors.lastname: Kim
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Young Lyun
authors.initials: YL
authors.lastname: Oh
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hye Jeong
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Endocrinology and Metabolism, Chosun University Hospital, Chosun University School of Medicine, Gwangju, Korea.
authors.forename: Sang Yong
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Chung
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea. swkimmd@skku.edu.
authors.forename: Sun Wook
authors.initials: SW
authors.lastname: Kim
keywords: Biopsy, fine-needle; Reliability; Thyroid nodule; Ultrasonography; Validity