what is a goitre
Introduction. A goitre (sometimes spelt  goiter ) is an abnormal swelling of the thyroid gland that causes a lump to form in the neck. There can be many possible causes, including an under-or overactive thyroid gland, iodine deficiency and, rarely, thyroid cancer (see below).ntroduction. A goitre (sometimes spelt  goiter ) is an abnormal swelling of the thyroid gland that causes a lump to form in the neck. There can be many possible causes, including an under-or overactive thyroid gland, iodine deficiency and, rarely, thyroid cancer (see below).