Differential diagnosis from benign thyroid diseases
	Most malignancies of the thyroid gland are found among nodules appearing "cold" on a thyroid scintiscan, but thyroid cancer has been described in all types of thyroid enlargements, and still the majority of cold nodules are benign, leaving a great differential diagnostic problem. A special issue of this publication series has recently been devoted to the "Management of thyroid nodules" (Thyroid International 4/95). The present paper will therefore only focus on some of the features of a clinical presentation indicative of malignancy. Even though a rapidly growing mass in the thyroid gland is likely to be malignant (Table 1), it has to be born in mind that both a cyst, a haemorrhage in a cyst or adenoma, subacute thyroiditis (De Quervain), chronic thyroiditis of Hashimoto type may all present as rapidly growing masses and all of them may also be firm and can even appear fixed upon palpation. A single nodule in a male is more likely to be malignant compared to that in a female. Table 1: Characteristics of malignant thyroid nodules Rapidly growing or painful thyroid nodule Family history of thyroid cancer Exposure to neck irradiation in child-hood Hoarseness Firm and/or fixed nodule Cervical adenopathy Vocal cord paralysis Features strongly indicative of benign thyroid nodules include long duration without growth, multinodular or diffuse goitre, simple thyroid cyst, "hot" nodule on thyroid scintiscan, high levels of autoantibodies to thyroglobulin (TgAb) and/or thyroperoxidase, a family history of benign goitre and a suppressed serum TSH.