![]() Posterior comet-tail artifacts found in association with echogenic foci in thyroid nodules have also been strongly associated with benignity. found that nonshadowing brightly echogenic linear foci with or without comet-tail artifact are associated with benignity. described peripheral calcification and purely cystic composition as statistically significant indicators of benignity. described four morphologic patterns found to have 100% specificity for benignity: spongiform configuration, cyst with colloid clot, giraffe pattern (typically associated with Hashimoto thyroiditis), and diffuse hyperechogenicity. Thyroid ultrasound findings specific for benignity can be used as justification for avoiding FNA. Benignity has been found to be associated with nodules that appear to be more cystic at ultrasound, particularly if they contain echogenic foci with posterior comet-tail artifacts. ![]() Ultrasound findings associated with increased malignancy risk (and thus typically warranting FNA) include microcalcifications, nodules that are more solid than cystic, coarse calcifications, and increased size and rate of growth compared with previous examination findings. Several groups have described characteristics discernible at ultrasound that support benignity or malignancy, and various organizations have used these characteristics to derive FNA guidelines for thyroid nodules. Definitive diagnosis is typically based on fine-needle aspiration biopsy (FNA) or surgical pathologic findings. Nodules incidentally discovered at ultrasound have a 5–15% malignancy rate depending on associated risk factors. ![]() The prevalence is known to be higher among women and with increasing age. At ultrasound examinations, as many as 60% of patients are found to have nodules. Thyroid nodules, palpable or otherwise, are common, having an overall prevalence of 50.5% among individuals with no known thyroid abnormality at autopsy. Keywords: cancer, colloid, echogenic focus, fine-needle aspiration, thyroid nodule With the exception of nodules that have peripheral calcifications, the risk of malignancy is low when echogenic foci are present in partially cystic lesions. Nodules with small comet-tail artifacts have a high incidence of malignancy in hypoechoic nodules. Identification of large comet-tail artifacts suggests benignity. ![]() All categories of echogenic foci except those with large comet-tail artifacts are associated with high cancer risk. Identification of one additional type of high-risk focus increased the chance of malignancy 1.48 times.ĬONCLUSION. Nodules with peripheral calcifications had prevalence rates of 20.0% in cystic nodules and 11.1% in predominately solid nodules. For internal calcifications, no malignant nodules were found in either partially cystic group. Foci with small comet-tail artifacts had a 27.6% rate of malignancy in hypoechoic nodules. Foci without posterior artifacts had a 21.9% rate of cancer in hypoechoic lesions and 15.8% in hyperechoic lesions. The prevalence of malignancy ranged between 15.4% and 19.5% for all types of foci except large comet-tail artifacts (3.9%). ![]() A total of 704 nodules had echogenic foci 246 did not. Results were compared with the cytologic or surgical findings. Nodules were also classified into four parenchymal patterns: hypoechoic, hyperechoic, > 50% solid, and cystic. Echogenic foci were classified into five types: no posterior artifact, large comet-tail artifact, small comet-tail artifact (≤ 1.0 mm), and posterior shadowing (subdivided into internal versus peripheral). Whether these findings were indicative of benignity or malignancy was assessed. This study was undertaken to define and evaluate echogenic foci and their posterior acoustic artifacts in thyroid nodules. ![]()
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