They may vary depending upon the type of carcinoma (or cancer):

  • Papillary and medullary carcinoma may have local and distant metastasis (spread of cancer)
  • One third of cases of medullary carcinoma may secrete serotonin and prostaglandins causing flushing and diarrhea. It may also be associated with phaeochromocytomas (tumor of adrenal gland ) or hyperparathyroidism (increased activity of parathyroid gland located just behind the thyroid)
  • Complications for thyroid surgery include:
    • Hypothyroidism is expected and should always be treated adequately with thyroid hormone therapy.
    • vocal cord paralysis (less common)
    • Hypoparathyroidism (if accidentally the small parathyroid gland located behind the thyroid gland are removed).