A change from a benign FNAC result to a malignant/suspicious one was present in more than 13% of the patients with initially benign cytology: malignancy has been recognised on the basis of repeated FNAC in 2.3% patients. In the majority of cases, the repetition corrected wrong cytological interpretation of results other than colloidal goitre, especially Hashimoto´s thyroiditis and regressive changes.
We believe that repeating FNAC in patients with benign cytology in about a 1-year horizon can reduce the rate of undiagnosed tumours.