Under this protocol, samples of FNAB, benign nodules and cancer tissue specimens, blood samples for research studies will be collected to assess new immunohistochemical and molecular markers, and other techniques to characterize tumors for correlation with diagnosis, response to therapy and prognosis. Blood and urine specimens will be collected for future clinical and research studies in both the hypothyroid and euthyroid state. Coded clinical data will be entered in the National Thyroid Cancer Registry in selected patients.