Table 1.
Bethesda system for reporting thyroid cytopathology: diagnostic categories and risk of malignancy3
| Bethesda category | Cytopathologic category | Approximate expected frequency | Malignancy rate | suggested treatment (Prior to availability of molecular testing) |
|---|---|---|---|---|
| I | Nondiagnostic/inadequate | 5-11 | 1-4 | Repeat FNA |
| II | Benign | 55-74 | 0-3 | US follow up |
| III | Atypia/follicular lesion of undetermined significance | 5-15 | 5-15 | Repeat FNA in 3-6 months |
| IV | Follicular neoplasm/suspicious for FN | 2-25 | 15-30 | Lobectomy |
| V | Suspicious for malignancy | 1-6 | 60-75 | Lobectomy or thyroidectomy |
| VI | Malignant | 2-5 | 97-99 | Total thyroidectomy |