Endocrine Abstracts

Introduction: Fine-needle aspiration (FNA) is indicated in suspicious thyroid nodules or big ones. Bethesda system classifies them according to the cytological malignancy risk. Bethesda category 4 (B4) comprises follicular neoplasms and suspicious follicular neoplasms. Aim: Determine final diagnosis of B4 nodules and study associations between malignancy and other variables.

Methods: Retrospective study of patients with nodules classified as B4 after FNA in our hospital between 2013 and 2017. Statistical analysis: SPSS v.19.0 (Student’s t test to compare means and χ²/Fisher’s test for proportions).

Results: 141 patients, 73.8% women, mean age: 53.33±14.90. 76.6% evaluated by the Endocrinology service prior to the FNA (21.3% previous thyroid pathology; 87.2% normal function). Symptoms: 88.7% asymptomatic. 5.7% cervical pain, 3.5% dysphonia, 3.5% dysphagia. Nodule discovery: 49.6% accidentally discovered in imaging studies done for other reasons, 35.5% palpation, 8.5% symptoms related to the nodule and 6.4% in routine follow-up sonography (US). Sonography characteristics: maximum diameter: 30.93±16.88 mm. 82.3% solid, 56.7% hypoechoic, 30.5% hypervascular, 9.2% coarse calcifications, 4.3% suspicious adenopathies and 1.4% microcalcifications (In the US 9.9% suspicious, 11.3% non-suspicious, 78.8% undetermined). 20.5% of them with previous FNA (1.4% B2, 7.8% B1, 11.2% B3). 84.4% patients underwent surgery (39.5% total thyroidectomy), 114.54±84.97 days after FNA. Final diagnosis: 77.3% benign (73.9% adenoma, 15.2% noninvasive follicular thyroid neoplasm with papillary-like nuclear features [NIFTP], 10.9% nodular goiter) and 22.7% malignant (51.9% follicular carcinoma, 40.7% papillary carcinoma, 7.4% medullary carcinoma). Most prevalent diagnosis after surgery: 33.6% folicular adenoma, 21.8% Hürthle adenoma, 11.8% NIFTP. Incidental microcarcinoma in 12.6% of interventions. Association with malignancy: Cervical pain (1.8 vs 20%, P=0.010), bigger maximum diameter (15.88±1.72 vs 18.27±3.23 mm, P=0.009). Tendency to association with malignancy: microcalcifications (0 vs 7.1%, P=0.068), hypoechogenicity (65.3 vs 89.5%, P=0.076).

Conclusions: 1) Incidentally discovered nodules equals clinically discovered ones.

2) Prevalence of malignancy in nodules classified as B4 is similar to the one reported in previous publications.

3) There is a statistically significative association between malignancy and clinical finding (cervical pain) and sonographic findings (bigger nodule size), as previously reported in the literature.