Benign Lesions that Mimic Thyroid Malignancy on Ultrasound

Utility of including BRAF mutation analysis with ultrasonographic and cytological diagnoses in ultrasonography-guided fine-needle aspiration of thyroid nodules

This study investigated the role of BRAF mutation analysis in thyroid fine-needle aspiration (FNA) samples compared to ultrasonographic and cytological diagnoses. A total 316 patients underwent ultrasonography (US)-guided FNA with BRAFV600E mutation analysis to diagnose thyroid nodules. One hundred sixteen patients with insufficient US images (n = 6), follow-up loss (n = 43), or unknown final diagnosis (n = 67) were excluded from the study. Comparisons between US diagnoses, cytological diagnoses, and BRAF mutation analysis were performed. Of 200 thyroid nodules, there was US diagnosis with 1 false negative and 11 false positive cases, cytological diagnosis with 10 false negative and 2 false positive cases, and BRAFV600E mutation analysis with 19 false negative and 2 false positive cases. The sensitivity, specificity, positive and negative predictive values, and accuracy of BRAFV600E mutation analysis were 83.2%, 98.1%, 97.5%, 86.6%, and 91%, respectively. Of the 18 nodules with Bethesda category III, 9 were true positive, 6 were true negative, 3 was a false negative, and none were false positive on BRAF mutation analysis. In conclusion, we recommend that BRAFV600E mutation analysis only be performed for evaluating thyroid nodules with Bethesda category III, regardless of US diagnosis.

Ultrasonographic Interval Changes in Solid Thyroid Nodules after Ultrasonography-Guided Fine-Needle Aspiration

Objective

None of the previous studies have investigated the interval change in ultrasonography (US) features of solid thyroid nodules (STNs) after US-guided fine-needle aspiration (US-FNA). This study aimed to assess the prevalence and characteristics of US interval changes in STNs after US-FNA.

Materials and Methods

This study included 257 STNs in 257 patients in whom thyroid US and initial US-FNA had been performed by two radiologists from January 2015 to June 2015. One of the radiologists performed single needle puncture in all cases, whereas the other radiologist used double or triple needle punctures. Follow-up US examinations were performed after 12.0 ± 6.0 months. We evaluated the prevalence and characteristics of post-FNA US interval changes through a retrospective analysis. In addition, multiple factors were correlated with post-FNA US interval changes.

Results

The number of needle punctures was one (n = 91), two (n = 163), and three (n = 3). Of the 257 STNs (mean diameter, 11.9 mm) in 257 patients, 35 (13.6%) showed an interval change in US features on follow-up US. Among them, 17 STNs (6.6%) showed newly developed malignant US features, including hypoechogenicity (n = 5), microcalcifications (n = 2), a spiculated margin (n = 4), hypoechogenicity with a spiculated margin (n = 5), and microcalcifications with non-parallel orientation (n = 1). Between patients who showed presence and absence of US interval changes, there were no significant differences in patient age, sex, nodule size, dichotomization, and location, Korean Thyroid Imaging Reporting and Data System categorization after FNA, practitioners involved, number of needle punctures, cytological findings, and interval between FNA and US follow-up (p > 0.05).

Conclusion

Awareness of US interval changes after US-FNA of STNs may be helpful for the management of STNs.

Sonographic Characteristics and Interval Changes of Subacute Thyroiditis

OBJECTIVES

This study aimed to assess the sonographic characteristics and interval changes of subacute thyroiditis using follow-up sonography.

METHODS

From January 2008 to December 2014, 85 patients with clinically suspected subacute thyroiditis underwent sonographic examinations by a single radiologist. Subacute thyroiditis was confirmed on the basis of the clinical, sonographic, and cytohistopathologic findings. On the initial and follow-up sonograms, the individual sonographic findings and interval changes were retrospectively investigated by the same radiologist. According to the sonographic configuration, subacute thyroiditis lesions were categorized as nodular or non-nodular. The interval changes in the lesions were classified as follows: "disappeared," "decreased," "increased," "eventually smaller," "eventually larger," or "no interval change."

RESULTS

Subacute thyroiditis was confirmed in 64 of the 85 patients. In these 64 patients, nodular (n = 39) and non-nodular (n = 35) lesions were found; 10 patients had both nodular and non-nodular lesions. Of the 64 patients, 41 underwent sonographic follow-up. In both nodular and non-nodular lesions, the common interval changes included disappeared, decreased, and eventually smaller patterns. Although the increased pattern was found only in 4 nodular lesions, there was no significant difference in the interval changes between nodular and non-nodular lesions. On follow-up sonography, a new lesion was detected in 6 patients.

CONCLUSIONS

The prevalence rate of nodular subacute thyroiditis lesions on sonography was high, and the interval changes in the lesions were variable.

Sonographic Features of Thyroidal Fatty Lesions in the Thyroid Gland: A Preliminary Study

OBJECTIVE

To my knowledge, no previous study has evaluated the sonographic features of thyroidal fatty lesions. The present study aims to assess the features of thyroidal fatty lesions as seen on ultrasound images and to determine the frequency of such lesions.

MATERIALS AND METHODS

From January 2013 to December 2014, a total of 940 patients underwent preoperative ultrasound and CT examinations of the neck before undergoing thyroid surgery. The criterion for the diagnosis of thyroidal fatty lesions was the presence of intraglandular fatty tissue on CT images, regardless of lesion size. One radiologist retrospectively analyzed all the ultrasound and CT images of these patients.

RESULTS

Of the 940 patients whose images were reviewed, 20 (2.1%) had thyroidal fatty lesions noted on neck CT and 17 of these 20 patients had thyroidal fatty lesions (mean of largest diameter, 6.3 mm; range, 4.8-9.2 mm) noted on ultrasound. The 20 involved sites included the right lobe (n = 11), the left lobe (n = 9), and the isthmus (n = 0). For 17 of these 20 cases (85%), continuity with the adjacent thyroid capsule or perithyroidal fatty tissue was seen on ultrasound or CT. All thyroidal fatty lesions showed hyperechogenicity, no calcification, no posterior shadowing or enhancement, and an ovoid shape, and most thyroidal fatty lesions had inhomogeneous echogenicity and a smooth margin.

CONCLUSION

On ultrasound images, thyroidal fatty lesions characteristically appear as ovoid inhomogeneously hyperechoic thyroid nodules with no calcification, no posterior shadowing or enhancement, a smooth margin, and continuity with the adjacent thyroid capsule or perithyroidal fatty tissue.