Endocrine Abstracts

Objective: Thyroid nodules (TN) are extremely common in the general population. Data on long-term follow-up of benign nodular thyroid disease are limited. The aim of our study was to evaluate the changes in ultrasound features in a group of patients with TN.

Methods: We retrospectively collected data about ultrasound features of 228 nodules from 153 consecutive patients with mean age 54.73±11.55 years [125 F (81.7%), 28 M (18.3%)], followed for a median period of 5 years in the Endocrinology Unit of Pisa Hospital. Nodule volume (V) was calculated using the ellipsoid formula. Nodules smaller than 0.065 ml³ were excluded and, according to the initial V, were divided in 2 groups: A if V ≤ 1 ml and B if V > 1 ml.

Results: 138/153 (90.2 %) patients had normal serum TSH values (0.4-4 mUI/l), 5/153 (3.3%) had TSH < 0.4 mUI/l and 10/153 (6.5%) had TSH > 4 mUI/l. 84/153 (54.9%) patients had positive thyroid autoantibodies (TAb), while 69/153 (45.1%) had negative TAb. Table 1 shows the thyroid nodules % volume variation (%V) compared to the initial volume. %V was not significative different in the whole group, while a significative increase was observed in subgroup B. Nodules were considered increased or reduced if their final V was higher or lower, respectively, of at least 30% compared to the initial V. At the end of follow-up, in group A, 53/148 (35.8%) nodules remained stable, 61/148 (41.2%) showed an increased V, 34/148 (23.0%) a reduced V; in group B 31/80 (38.8%) nodules remained stable, 24/80 (30.0%) showed an increased V and 25/80 (31.3%) a reduced V. The age of patients with increased V nodules (50.8±12.4 years) was significative lower compared to patients with stable nodules (57.8±9.7 years) (P < 0.05). The frequency of stable, increased, and reduced TN was not significantly different when sex, TAb positivity, mean serum TSH values, and the presence of single or multiple nodules were considered.

Conclusions: During follow-up, we observed an increased volume of TN with an initial V>1 ml, while smaller TN did not show significative differences, probably due to the high variability in ultrasound measurements of small TN. TN growth was higher in younger patients and was not significantly associated with sex, TAb positivity, mean serum TSH values, and the presence of single or multiple nodules.