The predictive value of dominant nodules and the management of indeterminate group in multinodular goiter

The objectives of this study were to determine the predictive value of dominant nodules (DNs) in multinodular goiters (MNGs), and to stratify the risk of malignancy within the indeterminate category. The study design was retrospective study of patients with MNG. A total of 140 patients were reviewed. Fine needle aspiration biopsy (FNAB) findings for all DNs were categorized into four groups: (1) benign, (2) positive or suspicious for malignancy, (3) indeterminate, and (4) non-diagnostic. All FNAB specimens of the indeterminate group were also evaluated for the presence of Hurthle cell metaplasia and were categorized according to the presence of cytological atypia. Cytohistological comparison was then performed. Mean number and diameter of the DNs were 1.45 and 25.6 mm, respectively. Based on final histopathology, 22.14% of the patients had thyroid malignancy and 74.2% of thyroid carcinomas were located in DNs. The number of DNs was significantly larger in malignant thyroid glands than in benign ones. In total, 22.6% of the indeterminate FNABs were malignant. FNABs of the indeterminate group that included atypical cells had a statistically significant higher incidence of malignancy. The presence of Hurthle cells was not statistically different in malignant and benign nodules upon final histological diagnosis. In conclusion, FNAB of only DNs in MNG could determine thyroid malignancy in 75% of patients. The DN number might be required for the predictive value of malignancy. A subclassification of the indeterminate group, based on the presence or absence of cytological atypia, is necessary to better assess the risk of malignancy.