Sonographic Features Predictive of Thyroid Nodule Malignancy in a Nigerian Population

Aims: To determine the ultrasound malignancy score (UMS) and identify the ultrasound (US) features of thyroid nodule (TN) associated with malignancy, in our study population, using fine-needle aspiration cytology (FNAC) as the gold standard.

Study Design: A prospective observational study.

Place and Duration of Study: Departments of Radiology and Morbid Anatomy and Forensic Medicine, Obafemi Awolowo University Teaching Hospital Complex, Ile Ife, Nigeria, between June 2016 and May 2017.

Methodology: We studied 110 thyroid nodules in 110 adult subjects (97males and 13males). Neck ultrasound scan (USS) to evaluate and score 7 sonographic features of the nodules for their malignant potential as well as simultaneous Ultrasound Guided Fine Needle Aspiration (USG-FNAC) was done. The findings were compared and data was analyzed using Statistical Package for Social Science (SPSS) version 20.

Results: USG-FNAC findings showed that of the 110 thyroid nodules studied, 107(97.3%) were benign while 3(2.7%) were malignant. Receiver operating characteristic curve showed that at sensitivity and specificity of 66.7% and 88.8% respectively giving UMS of 4.5. All the 3 nodules that were malignant on USG-FNAC had micro calcification and irregular margins on ultrasound (p=0.05).

Conclusion: Using USG-FNAC as the gold standard, thyroid nodules with UMS of 4.5 are likely to be malignant. Ill-defined margins and micro calcifications on ultrasound are suggestive of malignancy in thyroid nodules.