Differential diagnosis of diffuse sclerotic thyroid papillary carcinoma and Hashimoto's thyroiditis using fine‐needle aspiration cytology, BRAF^V600E, and ultrasound elastography

Abstract

Background The diffuse sclerosing variant of papillary thyroid carcinoma (DSV‐PTC) has ultrasound findings that are similar to Hashimoto's thyroiditis (HT), resulting in under‐diagnosis. DSV‐PTC combined with HT is also common, so early and accurate diagnosis of DSV‐PTC using a variety of diagnostic techniques, including FNAC, BRAFV600E mutation detection, and ultrasound elastography, is critical. Objective To assess the diagnostic value of fine‐needle aspiration cytology (FNAC) and BRAFV600E detection in combination with ultrasound elastography in the diagnosis of DSV‐PTC. Methods We performed a retrospective analysis of 40 patients with pathologically confirmed DSV‐PTC and 43 patients with HT admitted to our hospital's ultrasound department between January 2015 and December 2020. Preoperative FNAC, BRAFV600E mutation detection, and ultrasound elastography imaging were all performed on all patients. For a definitive diagnosis, the results of these tests were compared to postoperative pathological findings. The diagnostic value of FNAC, BRAFV600E mutation detection, ultrasound elasticity imaging, and their combination for DSV‐PTC diagnosis was assessed. Results The mean elastic strain rate ratio (E1/E2) of the 40 DSV‐PTC cases was 5.75 ± 2.14, while that of the 43 HT cases was 2.81 ± 1.20. The receiver operating characteristic (ROC) curve was generated using the average value of E2/E1. The area under the ROC curve was 0.910, and the optimal E2/E1 cut‐off value was 4.500. When FNAC, BRAFV600E mutation detection, and ultrasound elasticity imaging detection were combined, the diagnostic sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of DSV‐PTC diagnosis were 92.5%, 95.3%, 93.2%, 94.9%, and 94.0%, respectively, which were significantly higher than the single technique (p < 0.05). Conclusions The use of FNAC, BRAFV600E mutation detection, and ultrasound elastography in combination is more helpful in establishing an accurate diagnosis of DSV‐PTC than using a single diagnostic technique alone.

Expanding the role of ultrasound in the diagnosis of thyroid carcinoma and the wish for adjunctive diagnostic tools

“…9,10 The relevance of the restrictions of the TIRADS classification system and following diagnostic work up with FNAC, is illustrated by the article by Anomynous et al in this issue of the journal. 11 They report on a rare and aggressive subtype of PTC, that is, diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC), that is easily missed by applying the TIRADS ultrasound criteria. This is due to the fact that the ultrasound findings of DSV-PTC resemble those of commonly prevalent Hashimoto's thyroiditis (HT).…”