Clinical and ultrasound characteristics distinguishing benign and malignant thyroid nodules in Johannesburg, South Africa

Background: The detection of thyroid nodules is increasingly common in clinical practice owing to the widespread use of ultrasonography. Objectives: The aims of this study were to describe the clinical and biochemical characteristics of patients undergoing fine-needle aspiration (FNA) of thyroid nodules and to assess the ultrasound, cytologic and, where relevant, histologic features of thyroid nodules in this cohort. Methods: A retrospective study was conducted of 313 patients undergoing FNA at a private hospital in Johannesburg from October 2015 to July 2019. Demographic, clinical and biochemical data were recorded. Ultrasound features were graded according to the American Thyroid Association (ATA) guidelines and cytology was reported according to the Bethesda System for Reporting Thyroid Cytopathology. Results: The mean (SD) age of patients in this study was 48.0 (12.7) years and 250 (80.1%) were female. White and Asian/Indian patients made up 79% of the cohort. Cytology results showed the following (n [%]): benign, 272 (86.9); indeterminate, 15 (4.79); suspicious/malignant, 25 (7.99). Sonographic characteristics associated with malignancy were microcalcifications and hypoechogenicity (OR [95% CI], p-value: 3.93 (1.62, 9.53), p = 0.001and 2.34 (1.01, 5.41), p = 0.04, respectively). There was an association with the composite ATA score and malignancy (3.59 [2.06, 6.25], p < 0.0005). Conclusion: Thyroid ultrasound and FNA are important diagnostic modalities in identifying clinically relevant thyroid nodules. Concordance was shown with the ATA guidelines, Bethesda System for Reporting Thyroid Cytopathology and malignant histology, which validates their accuracy in the local population.