The number of newly diagnosed cases of thyroid carcinoma reported annually averages 750, the majority presenting as a solitary thyroid nodule that proves to be well-differentiated and carries a good prognosis. Solitary nodules are comparatively common and must be investigated further, since approximately twelve per cent that are ΓÇÿcoldΓÇÖ on radioactive iodine or pertechnetate scan (i.e. take up less radioactivity than the surrounding normal thyroid) prove to be malignant. This percentage is higher still in children and young adults. Anaplastic thyroid carcinoma is rapidly fatal, but is much rarer and occurs mostly in the elderly.
