Thyroid cancer is the most common endocrine malignancy, and incidence is rising. MAP kinase (MAPK) signaling has been implicated in playing a critical role in the initiation and maintenance of thyroid cancer, as evidenced by the high incidence of non-overlapping mutations of the genes encoding RET and TRK, as well as of NRAS, HRAS, KRAS, and BRAF. Although pediatric and adult thyroid cancers have been found to share many of the same driver mutations, it is not yet known and validated in pediatric populations whether molecular testing can improve diagnostic accuracy, particularly in ruling out malignancy. Further, it is not yet clear in pediatric populations whether microRNA expression can improve diagnostic accuracy. We sought to determine whether a 10-microRNA classifier developed and optimized for adult thyroid lesions could improve the diagnostic accuracy of thyroid nodules in pediatric patients. In future studies we plan to use these preliminary findings to further understand the molecular differences that drive the differential pathogenesis of pediatric versus adult tumors, despite sharing identical driving mutations.