Reliability of Thyroid Imaging Reporting and Data System (TI-RADS), and ultrasonographic classification of the American Thyroid Association (ATA) in differentiating benign from malignant thyroid nodules

ABSTRACT Objective Ultrasonography (US) is the best diagnostic tool for initial assessment of thyroid nodule. Recently, data reporting systems for thyroid lesions, such as the Thyroid Imaging Reporting and Data System (TI-RADS) and American Thyroid Association (ATA), which stratifies the risk for malignancy, have demonstrated good performance in differentiating malignant thyroid nodules. The purpose of this study is to determine the reliability of both data reporting systems in predicting thyroid malignancy in a tertiary care hospital. Materials and methods We evaluated 195 thyroid nodules using modified TI-RADS and ATA risk stratification. The results were compared to the cyto-pathology analysis. Histopathological results were available for 45 cases after surgery, which is considered the golden standard for diagnosis of thyroid cancer. Results When compared with cytological results, sensitivity, specificity, negative predictive value (NPV), and accuracy were 100, 61.1, 100, and 63%, respectively, for TI-RADS; and 100, 75, 100, and 76%, respectively, for ATA. When compared with histopathological results, sensitivity, specificity, NPV, and accuracy were 90, 51.4, 94.7, and 60% respectively, for TI-RADS; and 100, 60, 100, and 68%, respectively, for ATA. All patients with malignant nodules were classified in the categories 4 or 5 of TI-RADS and in the intermediate or high suspicion risk according to the ATA system. Conclusion Both TI-RADS and the ATA guidelines have high sensitivity and NPV for the diagnosis of thyroid carcinoma. These systems are feasible for clinical application, allowing to better select patients to undergo fine-needle aspiration biopsies.

Painless thyroiditis associated to thyroid carcinoma: role of initial ultrasonography evaluation

Even though it is a rare event, most associations of thyroid carcinoma with subacute thyroiditis described in the literature are related to its granulomatous form (Quervain’s thyroiditis). We present a patient with subacute lymphocytic thyroiditis (painless thyroiditis) and papillary thyroid cancer that was first suspected in an initial ultrasound evaluation. A 30-year old female patient who was referred to the emergency room due to hyperthyroidism symptoms was diagnosed with painless thyroiditis established by physical examination and laboratory findings. With the presence of a palpable painless thyroid nodule an ultrasound was prescribed and the images revealed a suspicious thyroid nodule, microcalcification focus in the heterogeneous thyroid parenquima and cervical lymphadenopathy. Fine needle aspiration biopsy was taken from this nodule; cytology was assessed for compatibility with papillary thyroid carcinoma. Postsurgical pathology evaluation showed a multicentric papillary carcinoma and lymphocytic infiltration. Subacute thyroiditis, regardless of type, may produce transitory ultrasound changes that obscure the coexistence of papillary carcinoma. Due to this, initial thyroid ultrasound evaluation should be delayed until clinical recovery. We recommended a thyroid ultrasound exam for initial evaluation of painless thyroiditis, particularly in patients with palpable thyroid nodule. Further cytological examination is recommended in cases presenting with suspect thyroid nodule and/or non-nodular hypoechoic (> 1 cm) or heterogeneous areas with microcalcification focus.