Endocrine Abstracts

Objective: To evaluate the outcome of fine needle aspiration biopsy (FNAB) of solid thyroid nodules, and the utility of thyroid ultrasound in determining the nature of solid nodules in our practice.

Methods: We reviewed the diagnostic outcome of FNAB of solid thyroid nodules in 93 patients from our dedicated thyroid biopsy clinic. In addition we compared the predictive value of sonographic assessment with FNAB in a subset of patients who had undergone both procedures. Samples were assessed for adequacy in the clinic by a cytology technician.

Results: In 24 male and 69 female patients, median age 53 (range 18–84 years), 91% of FNAB were adequate, yielding Thy 2 (64%), Thy 3 (21%), Thy 4 (2%) and Thy 5 (2%) outcomes respectively. 51 benign colloid nodules, 14 follicular lesions, 2 Hurthle cell, 3 papillary, 1 medullary, and 1 anaplastic carcinoma were identified. 8.6% FNAB were classified as insufficient (Thy1), requiring reaspiration. 20 biopsies were Thy3 and 15 patients underwent surgery with histological outcomes of colloid nodule (10), hurthle cell carcinoma (1), follicular carcinoma (3), Hashimoto’s thyroiditis (1). 3 nodules yielded benign cytology on subsequent FNAB, 1 patient is awaiting surgery and 1 patient had lymphoma requiring chemotherapy. 3 of 4 Thy 4/5 FNAB proved to be malignant on histology and 1 was consistent with benign colloid nodule.

Fifty patients (53.7%) underwent thyroid ultrasound together with FNAB, enabling comparison of sonographic characteristics with cytological outcome.

Conclusion: Thyroid nodule FNAB was highly successful (91%) in a dedicated clinic with cytological and radiological support. However, 65% of Thy 3 lesions had a benign histological outcome, suggesting that further diagnostic modalities to evaluate indeterminate nodules and prevent unnecessary surgery are required. Ultrasound had a positive predictive value of 66% and negative predictive value of 86% confirming its utility in deciding which nodules to biopsy.