title: Predicting malignant involvement in a thyroid nodule: role of ultrasonography.
abstract: OBJECTIVE
  To assess how ultrasonography can contribute during the evaluation of a thyroid nodule and whether this technique can have a role in predicting malignant involvement.
  
  
  METHODS
  In this retrospective study, data were analyzed on 220 consecutive patients (with 348 thyroid nodules) who underwent thyroidectomy and had previously undergone assessment by high-resolution thyroid ultrasonography. Nodule size, echogenicity, regularity of margins, halo sign, presence or absence of calcifications, and invasion of surrounding tissues were evaluated. The nodules were classified as low, medium, or high risk for malignant involvement on the basis of nodule characteristics found on ultrasonography. All nodules were submitted to cytologic examination by fine-needle aspiration (FNA) before thyroidectomy. Ultrasound, FNA, and pathologic postoperative results were compared.
  
  
  RESULTS
  Among the 348 thyroid nodules, 56 were ultrasonographically classified as low risk, 268 as medium risk, and 24 as high risk for malignant potential. Fifty of 56 (89.3%) low-risk nodules and 213 of 268 (79.5%) medium-risk nodules were diagnosed as benign at pathologic postoperative examination. In contrast, however, only 6 of 24 (25%) high-risk nodules were diagnosed as benign. Among the 18 high-risk nodules of 1-cm diameter or larger, FNA showed a 20% false-negative result.
  
  
  CONCLUSIONS
  High-risk classification of a thyroid nodule on ultrasonography had a positive predictive value for malignant involvement of 75%. Nodule characteristics analyzed by ultrasonography should be considered at the time of surgical intervention.
authors.affiliation: Department of Endocrinology, Centro de Endocrinologia de Natal, Natal-RN, Brazil.
authors.forename: Lucia H C
authors.initials: LH
authors.lastname: Nóbrega
authors.forename: Fernando J P
authors.initials: FJ
authors.lastname: Paiva
authors.forename: Maria L C
authors.initials: ML
authors.lastname: Nóbrega
authors.forename: Luiz E B
authors.initials: LE
authors.lastname: Mello
authors.forename: Hermano A F
authors.initials: HA
authors.lastname: Fonseca
authors.forename: Saul O
authors.initials: SO
authors.lastname: Costa
authors.forename: André G P
authors.initials: AG
authors.lastname: Sousa
authors.forename: Denise B F M
authors.initials: DB
authors.lastname: Leite
authors.forename: Josivan G
authors.initials: JG
authors.lastname: Lima
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D044963:Biopsy, Fine-Needle; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D013965:Thyroidectomy; D014463:Ultrasonography