Jae Young Seo, Abstract Co-Author: Nothing to Disclose

Keum Won Kim MD, Presenter: Nothing to Disclose

Hee Jung Moon MD, Abstract Co-Author: Nothing to Disclose

Eun-Kyung Kim, Abstract Co-Author: Nothing to Disclose

Jin Young Kwak MD, Abstract Co-Author: Nothing to Disclose

Combination of the BRAFV600E mutation with cytologic results can improve the diagnostic performance of papillary thyroid carcinoma (PTC). However, it is unclear whether routine molecular tests should be done considering cost-effectiveness. Therefore, we investigated the additional diagnostic yield of the mutation test and evaluated the frequency of the BRAF mutation in conventional PTC (cPTC) according to US features and the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) based on the BRAFV600E mutation status confirmed through cytologic or resected tumor samples.

During the study period, 279 patients who underwent FNA with an additional BRAFV600E mutation test were diagnosed as conventional PTC after surgery. We analyzed the association between the mutation and several clinical factors.

Of the 279 cPTCs, 250 (89.6 %) had the BRAFV600E mutation. Among the clinicopathologic features, only taller than wide shape showed a statistically significant association with the mutation (P= 0.029). Among PTCs with the BRAFV600E mutation, the highest detection rate of the mutation in FNA washouts was 96.2 % in PTCs with malignant cytology. The detection rates of the mutation in FNA washouts of PTCs with the BRAFV600E mutation were statistically different according to the BSRTC. Among PTCs except for ones of malignant cytology, 53 PTCs showed the mutation in FNA washouts. The BRAF mutation test was helpful in diagnosing an additional 19% (53/279) of PTCs. When we evaluated the frequency of the BRAF mutation in cPTCs based on US features according to the BSRTC, the frequency of the BRAF mutation in cPTCs with suspicious US features was higher than that of cPTCs with negative US features regardless of the BSRTC.

A routine additional BRAFV600E mutation test may have a limited role in diagnosing PTCs. Instead, suspicious US features may be helpful in deciding whether an additional BRAFV600E mutation test should be done in thyroid nodules with indeterminate cytology. 

The BRAFV600E mutation test is a very ususeful additional tool to FNA for diagnosing papillary thyroid carcinoma (PTC).

Seo, J, Kim, K, Moon, H, Kim, E, Kwak, J, Clinical Implication of Highly Sensitive Detection of the BRAFV600E Mutation in Fine-Needle Aspirations in Patients with Conventional Papillary Thyroid Carcinoma according to the Thyroid Bethesda System.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13025960.html