NCIt definition : Enlargement of the thyroid gland usually caused by lack of iodine in the diet, hyperthyroidism,
or thyroid nodules. Symptoms include difficulty in breathing and swallowing.;
Alternative definition : NICHD: Enlargement of the thyroid gland.; NCI-GLOSS: An enlarged thyroid. It may be caused by too little iodine in the diet
or by other conditions. Most goiters are not cancer.;