The BRAFT1799A Mutation is not Associated with Occult Contralateral Carcinoma in Patients with Unilateral Papillary Thyroid Microcarcinoma

Background: The phenomenon of occult carcinoma maybe observed in patients with clinically unilateralpapillary thyroid microcarcinoma (PTMC). Although many studies have reported that the BRAFT1799A mutation isassociated with aggressive PTMC, the relationship between BRAFT1799A mutation and occult carcinoma is unclear.The aim of this study was to investigate the risk factors, including BRAFT1799A mutation, for occult contralateralcarcinoma in clinically unilateral PTMC accompanied by benign nodules in the contralateral lobe. Materialsand
Methods: From January 2011 to December 2013,we prospectively enrolled 89 consecutive PTMC patientswith clinically unilateral carcinoma accompanied by benign nodules in the contralateral lobe who received atotal thyroidectomy and cervical lymph node dissection. BRAFT1799A mutation was tested by pyrosequencing onpostoperative paraffin specimens. The frequency and predictive factors for occult contralateral carcinoma wereanalyzed with respect to the following variables: age, gender, family history, tumor size, presence of Hashimotothyroiditis, extrathyroidal extension, central lymph node metastasis, multifocality of primary tumor, or BRAFT1799Amutation.
Results: A total of 36 patients (40.4%) had occult PTMC in the contralateral lobe. The median diameterof the occult tumors was 0.33±0.21 cm. The BRAFT1799A mutation was found in 38 cases (42.7%). According to theunivariate analysis, there were no significant differences between the presence of occult contralateral carcinomaand age, gender, family history, tumor size, presence of Hashimoto thyroiditis, extrathyroidal extension, centrallymph node metastasis, multifocality of primary tumor, or BRAFT1799A mutation.
Conclusions: Using currentmethods, it is difficult to preoperatively identify patients with PTMC, and further research is needed to determinepredictive factors for the presence of occult contralateral carcinoma in patients with unilateral PTMC.