Overview of thyroid physiology: an essential for understanding familial euthyroid multinodular goiter.

Nontoxic goiter is a diffuse or nodular enlargement of the thyroid gland that does not result from an inflammatory or neoplastic process and is not associated with abnormal thyroid function. Familial forms of goiter in areas not known to feature iodine deficiency are much less common. However, not all individuals in the same iodine deficiency region develop goiter and iodine supplementation does not prevent goiter development in all treated individuals. The etiology of euthyroid goiter is still incompletely understood. It is assumed that the development of goiter depends on various interactions between genetic and environmental factors. We present an overview on the thyroid physiology, which is important for a better understanding of Familial Euthyroid Multinodular Goiter.