Endocrine Abstracts

Aim: Exophytic nodule refers to a nodule that sticks out of the normal thyroid boundary/outline. Other definition is a nodule with an acute angle between the lesion and adjacent thyroid capsule. In the literature, one study reported that thyroid nodules with exophytic configuration showed a high malignancy rate. We aimed to compare ultrasonographical features and cytopathologic results of exophytic and non-exophytic thyroid nodules.

Material and method: Thirty-four exophytic and 34 non-exophytic thyroid nodules in which fine-needle aspiration biopsy was indicated throughout 3 months were evaluated prospectively. Mean nodule size was similar in two groups (18.83±8.71 and 15.28±7.57 mm, P=0.173). The ratio of presence of peripheral hypoechoic halo and marginal irregularity was also similar in both group (P=0.512 and P=0.153 respectively). Microcalcification was present in 21.4 and 29.4% of exophytic and non-exophytic nodules respectively (P=0.424). Macrocalcification was detected in 4.5% of exophytic and 11.8% of non-exophytic nodules (P=0.111). 47.6% of exophytic nodules was hypoechoic and 52.4% was isoechoic. 47.1% of non-exophytic nodules was hypoechoic and 52.9% was isoechoic. Color flow Doppler pattern was defined as non-vascular, peripheral, central, or of mixed type and was similar in both groups (P=0.138). Cytopathologic results of exophytic nodules were 75% benign, 4.3% follicular lesion or atypia with undetermined significance, 2.3% suspicious for malignancy, 2.3% malign, and 15.9% non-diagnostic. In non-exophytic group, 79.4% was benign and 20.6% was non-diagnostic (P=0.497).

Conclusion: Exophytic configuration of thyroid nodules was rarely investigated as a possible predictive feature for malignancy in the literature. In this study, we did not find any difference in terms of ultrasonographical features and cytological results between exophytic and non-exophytic thyroid nodules. However, more comprehensive studies are needed to clarify any possible relation between exophytic configuration and malignancy.