Predictors of malignancy in preoperative nondiagnostic biopsies of the thyroid.

OBJECTIVE: To determine whether preoperative variables can be used to predict malignancy for thyroid nodules with follicular, Hürthle, or nondiagnostic cytology on fine-needle aspiration biopsy (FNAB).

MATERIALS AND METHODS: Retrospective analysis of 77 consecutive patients selected for total or subtotal thyroidectomy for follicular, Hürthle, or nondiagnostic lesions of the thyroid in two university hospitals. Eleven clinical variables, as well as nodule size, multiplicity, and ultrasound calcifications, were correlated with final histopathologic diagnosis of benign or malignant disease. Analysis was preformed using the Pearson chi-square test.

RESULTS: The overall rate of malignancy in our series was 61% (n = 47). FNABs classified as follicular or Hürthle lesions without cellular atypia had a significantly lower risk of malignancy (49% vs 71%; p = .05). Patients who presented with a solitary nodule and FNAB cellular atypia displayed an increased risk of malignancy (92% vs 55%; p = .011). The rate of malignancy was higher for patients with a positive family history (100% vs 59%), a solitary nodule (73% vs 53%), cellular atypia (76% vs 54%), or intrathyroidal calcifications on ultrasonography (71% vs 57%), although none were found to be statistically significant (p > .05). Male gender, age > 45 years, nodule size > 3 cm, mass effect symptoms, and radiation exposure to the neck were not associated with malignancy in our series.

CONCLUSION: When presented with follicular, Hürthle, or nondiagnostic biopsies for thyroid nodules, thyroid surgeons should rely systematically on sonographic findings and cytopathologic features to guide their management approach.