title: Inadequate cytology in thyroid nodules: should we repeat aspiration or follow-up?
abstract: BACKGROUND
  To evaluate how to correctly manage thyroid nodules showing inadequate cytology after ultrasound (US)-guided fine-needle aspiration biopsy (US-FNAB).
  
  
  METHODS
  A total of 393 thyroid nodules with inadequate cytology in 351 patients (M:F = 40:311, mean age: 49.3 years) with surgery or follow-up US-FNAB for at least 1 year were included in this study. Among them, 293 (74.6%) were benign and 100 (25.4%) were malignant on final reference results. Clinical characteristics and US features were reviewed and compared.
  
  
  RESULTS
  Malignancy rates (39.5%) of nodules having suspicious US feature were significantly higher than those (10.9%) of nodules without any suspicious US feature (P < .001). Malignancy rates of solid nodules, mainly solid nodules, and mainly cystic nodules were 29.2, 16.7, and 9.5%, respectively, with significant differences (P = .016). Malignancy rates of nodules assessed as suspicious malignant to probably benign in composition are: 39.1-12.8% (P < .001) in solid nodules, 42.1-9.2% (P = .001) in mainly solid nodules, and 50.0-5.3% (P = .04) in mainly cystic nodules.
  
  
  CONCLUSIONS
  In nodules with inadequate cytology, follow-up US can be considered over repeat aspiration if there are no suspicious US features present, especially in mainly cystic nodules.
authors.affiliation: Department of Radiology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Yoon
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Moon
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kwak
mesh_terms: D044963:Biopsy, Fine-Needle; D003581:Cytodiagnosis; D003584:Cytological Techniques; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000601:surgery; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000601:surgery; D014463:Ultrasonography