Table 1. Causes of thyroid enlargement (goiter).

Disease entity	Thyroid function	Remarks
Diffuse goiter	euthyroid
Uni- or multinodular goiter	euthyroid-hyperthyroid	in regions of iodine deficiency, may coexist with autoimmune thyroiditis
Thyroid cancer	euthyroid	may be present within a nodular goiter and/or autoimmune thyroiditis
Autoimmune thyroiditis	euthyroid, hypo- or hyperthyroid	thyrocyte destruction in Hashimoto’s thyroiditis, TSH-R-AB-mediated thyrocyte stimulation in Graves’ disease
De Quervain’s thyroiditis	euthyroid, hypo- or hyperthyroid	typically, tenderness of the thyroid; fever; poor general state
Riedel’s thyroiditis	euthyroid
Thyroid cyst	euthyroid
Impaired thyroxine synthesis	hypothyroid-euthyroid	TSH-triggered multinodular goiter
Thyroxine resistance	euthyroid	End-organ-dependent function
Acromegaly	euthyroid	IGF-1-dependent
Drugs (lithium, thyrostatic drugs)	euthyroid-hypothyroid
TSH-oma	hyperthyroid	TSH-dependent

IGF, insulin-like growth factor; TSH, thyroid-stimulating hormone; TSH-oma,TSH-secreting pituitary adenoma; TSH-R-AB, TSH-receptor antibodies