Head and Neck ImagingGoitre
(also called struma), chronic enlargement of the
thyroid gland. It occurs endemically in certain localities, and sporadically elsewhere, and is often caused by iodine deficiency.
A chronic multinodular goitre is commonly produced by nodular hyperplasia, in which the thyroid gland has a diffuse nodular aspect, without residual normal thyroid tissue. These nodules have different histological appearances, with small and large follicles and different kinds of regressive phenomena induced by ischaemia; progressive fibrosis of the nodules is seen, but intervening acute oedema, bleeding or necrosis is possible. These histological changes explain the common heterogeneous aspect of a goitre on imaging studies. Multinodular goitres are usually seen with eu- or hypothyroidism; they may turn into a toxic goitre when one or more hyperfunctioning nodules are present. Also, see thyroid gland.
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