Cytological findings in scintigraphically nonfunctioning thyroid nodules

Abstract

The major one among the procedures for evaluating changes in the thyroid nodules is fine needle aspiration biopsy (FNAB). Thyroid scintigraphy is commonly used in diagnostic algorithm of nodules. Less than 5% of examined nodules show to be malignant. Scintigraphically, nodules could be classified as functional and nonfunctional. It is estimated that the risk of malignancy in nonfunctional nodules ranges from 8% to 25% and more. Aspiration punction provides 100% specific and positive predictive value. The aim of the study was to establish the distribution of cytological findings in nonfunctioning thyroid nodules. The prospective study enrolled 112 patients, 104 women and 8 men, submitted to thyroid scintigraphy for known thyroid nodule disorder. Scintigraphy was performed about half an hour after iv administration of 74 MBq of sodium-pertehnetate. A pin hole collimator was used. Scintigrams were visually evaluated, and absence of radiopharmaceutic in a nodule was estimated as nonfunctional one. Such nodules were afterwards subjected to FNAB and material obtained was cytologically analyzed. In our patients nonfunctioning nodules comprised tissue of colloid struma, thyroid cyst, regular thyroid tissue, follicular lesion, oxiphillic lesion, papillary carcinoma tissue and tissue of lymphocytic thyroiditis. The most frequent cytological finding were colloid cysts (52%). A total of 70% were female nodules. Five cytological findings were histopathologically analyzed. Cytological finding of nonfunctional nodules determines of the decision on radical therapy, and our preliminary results imply the need of FNAB routine use in nuclear medicine practice.