Histologic analysis and comparison of techniques in fine needle aspiration-induced alterations in thyroid

OBJECTIVE: To assess histologic alterations following fine needle aspiration (FNA) of the thyroid and differentiate these from ominous lesions, such as papillary carcinoma thyroid, as well as assess and compare the degree of tissue trauma from the techniques: needle only vs. needle with syringe, size of needle and number of aspirations. STUDY DESIGN: Thyroidectomy specimens of 100 cases with prior FNA biopsy were selected. The changes called "worrisome histologic alteration following fine needle aspiration of the thyroid" (WHAFFT) were studied. Number of FNAs, needle size and technique were tabulated for 73 of 100 cases. RESULTS: Worrisome changes were confined to areas near the needle tract and hence could be differentiated from ominous lesions. Control cases did not show WHAFFT lesions. Non-aspiration FNA cytology (FNAC) technique results in fewer, less frequent WHAFFT changes. The increasing number of FNAs leads to statistically significant increase in infarction, necrosis and vascular changes. A gradation in the WHAFFT changes, directly proportional to the increasing diameter of the needle, was observed. CONCLUSION: The pathologist should be aware of WHAFFT to avoid misinterpretation. The technique of non-aspiration FNAC is significantly less traumatic. An increase in FNAs or size of needle results in more severe WHAFFT changes.