Ultrasound Findings in Thyroid Nodules: A Radio-Cytopathologic Correlation.

Introduction: Ultrasound (USG) can be a good screening tool to identify high-risk nodule requiring fine-needle aspiration cytology (FNAC). The study aimed to assess the association of USG characteristic of thyroid nodule with malignancy.

Methods: A cross-sectional study was performed from August 2011 to July 2012 at Tribhuvan University Teaching Hospital. Patients referred for USG of the neck with thyroid nodule more than 10 mm were offered FNAC and included in the study after taking informed consent. USG characteristics were compared with histopathologic diagnosis of benign or malignant nodule.

Results: USG characteristics significantly ( P < 0.05) associated with malignancy were as follows: size of thyroid nodule more than 30 mm, ill-defined margin, solid echotexture, hypoechoic lesion, microcalcification, and any form of increased vascularity. High sensitivity was seen in microcalcification, hypoechoic echogenicity, and ill-defined margin and high specificity was seen in ill-defined margin and solid echotexture. Relatively high sensitivity and specificity was found in ill-defined margin.

Conclusions: Texture, size, margin, echogenicity, and vascularity are important factors for discriminating benign from malignant nodule. Hypoechogenicity, vascularity of any type, ill-defined margin, and microcalcification were independent predictors of malignancy. None of the characteristics were sensitive and specific to be used independently as screening tool to identify high risk of malignancy.