BRAF and medullary thyroid gland carcinoma: Interestingly, two cases, one NRAS mutation positive and one HRAS positive, along with the previously mentioned BRAF positive case, were the only three where the presence of a mutation found in the abnormal cytology specimen did not correlate with a malignancy on surgical resection. Of these abnormal cytology specimens with a positive RAS mutation, the medullary carcinoma was the only previous specimen with a definitive positive for malignancy designation on cytology diagnosis alone; the others were placed in one of the indeterminate categories (AUS/FLUS, FN/SFN, or SM).