• Iodine deficiency is associated with follicular carcinoma , which is more common in iodine-deficient areas such
  as Germany. 
• Iodine abundance is associated with papillary carcinoma, more common in areas using iodized salt (United
  States) or a high-iodine diet (Iceland).
• Patients with Hashimoto's thyroiditis have an increased incidence of lymphoma of the thyroid gland.
• There is a slight increased risk of thyroid cancer in patients with chronic TSH (thyroid-stimulating hormone)
  elevation, usually as a congenital defect, or other thyroid abnormalities.