Fine-needle aspiration (FNA) of thyroid bed lesions after thyroidectomy is challenging to evaluate. We determined the sensitivity, specificity, and positive and negative predicative value of thyroid bed FNA (TB-FNA) for detecting local recurrence of thyroid carcinoma.
A retrospective search was conducted for TB-FNAs from patients with a prior thyroid resection and subsequent ipsilateral FNA from the thyroid bed. Clinical and pathologic data were retrieved from the medical record. Patients were ultimately classified as "malignant" or "benign" based on the worst pathology identified and follow-up available.
Forty-two cases were included, and the prior thyroidectomy pathology included 36 papillary thyroid carcinomas, two follicular carcinomas, one medullary carcinoma, and three benign cases. TB-FNA was adequate in 38 (90.5%) cases and interpreted as positive for malignancy (n = 22; 52.4%), suspicious for follicular neoplasm (n = 3; 7.1%), atypia of unknown significance (n = 2; 4.8%), and benign (n = 10; 23.8%). Twenty-seven patients had histologic follow-up, and 24 (87.5%) showed recurrent malignancy. The cytology sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 96%, 100%, 100%, 92.3%, and 97.4%, respectively, for identification of recurrent malignancy.
Most TB-FNA cases ultimately were diagnosed with malignancy on follow-up, although there may be sampling bias, as not all clinically benign cases had surgical follow-up.