Malignant: Malignant neoplasms account for 3-7% of FNA results, and the majority of malignant lesions are papillary thyroid carcinomas. The true positive rate for malignant lesions is 97-99%, meaning that approximately 1-3% of nodules diagnosed as malignant are likely to be benign. Malignant thyroid lesions usually include: a. papillary thyroid carcinoma b. medullary thyroid carcinoma c. undifferentiated thyroid carcinoma d. hypoplastic thyroid carcinoma e. squamous carcinoma f. mixed carcinoma g. metastatic carcinoma h. non-Hodgkin’s lymphoma, etc. Patients with a diagnosis of malignant lesions usually require surgery, except for non-Hodgkin’s lymphoma and undifferentiated thyroid carcinoma.