Fine-Needle Thyroid Aspiration Biopsy: Clinical Experience at the Endocrinology Clinics of the University Hospital of Puerto Rico

Abstract

Objective: This study aimed to establish a profile of the ultrasound-guided thyroid fine-needle aspiration biopsies (FNABs) performed at the endocrinology clinics of the University Hospital of Puerto Rico.

Methods: A retrospective study was conducted to assess all the thyroid FNABs performed from July 1, 2011, to December 31, 2013. Data on socio-demographic, FNAB cytology, surgery, and histopathology were collected from medical records. A chi-square test was used to assess associations between predictors and outcome. McNemar's test was used to compare FNAB cytology and histopathology results.

Results: A total of 240 FNABs were performed on 192 patients; 91.2% were female. The distribution of the cytological diagnoses was as follows: 181 (75.4%) were benign; 39 (16.3%) were non-diagnostic; 15 (6.3%) were indeterminate; and 5 (2.1%) were malignant. A malignant cytology was more likely in patients younger than 45 y/o than in their older counterparts (p = 0.01); a similar result was found for patients who smoked vs. those who did not (p = 0.02). Benign nodules were more likely to be larger than 1 cm than were those that were malignant (88.2% vs. 25%). Histopathology results were available for 38 nodules; there were no statistically significant differences between the cytology and histopathology results (p>0.05). The sensitivity and specificity for FNAB cytology were 75% and 100%, respectively. Of the nodules with an initial indeterminate cytology (47%), 71% demonstrated, ultimately, benign histopathology.

Conclusion: In our study, most of the FNABs performed yielded a benign cytology. A high concordance was shown between cytology and histology. For those with indeterminate cytology, the majority of cases demonstrated benign histopathology. These data suggest the need to implement other approaches, such as the development and subsequent use of molecular markers, to improve our diagnostic and therapeutic strategies, this according to our population-based disease prevalence.

Keywords: Cytology; Thyroid fine-needle aspiration biopsy; Thyroid nodules.

Figure 1

Distribution of Cytological results according to BSRTC^* BSRTC = Bethesda System for Reporting Thyroid Cytopathology; AUS = atypia of undetermined significance; FLUS = follicular lesion of undetermined significance; FN or SFN = follicular neoplasm or suspicious for follicular neoplasm; FNABs = Fine needle aspiration biopsies. *Assessment was made per nodule

Figure 2

Percent of surgeries performed at each cytological category AUS = atypia of undetermined significance; FLUS = follicular lesion of undetermined significance; FN or SFN = follicular neoplasm or suspicious for follicular neoplasm. *All nodules with Suspicious for malignancy/malignant cytologies were recommended surgery, but it was unknown if one of the nodules- in each of these categories had surgery.