Simple nontoxic goiter

[Sommer]

Simple nontoxic goiter is noncancerous enlargement of the thyroid gland.

Noncancerous thyroid enlargement can occur because of lack of iodine in the diet or ingestion of certain substances or drugs.
People often have no symptoms.
Doctors do blood tests to determine how well the thyroid is working.
Doctors may treat the cause of the enlargement, and sometimes people need surgery to remove part of the enlarged thyroid.

(See also Overview of the Thyroid Gland.)
The word goiter is sometimes used to describe any form of thyroid gland enlargement (for example, enlargement caused by inflammation or cancer). Simple, nontoxic goiter is a specific form of noncancerous enlargement.
The most common cause of simple nontoxic goiter in most of the world is

A diet that does not contain enough iodine (iodine deficiency)

The thyroid gland uses iodine to make thyroid hormone. When there is not enough iodine, the thyroid gland grows larger in an attempt to compensate. However, in the United States, most salt is fortified with iodine, so lack of iodine is not a common cause of goiter.
Other causes of simple nontoxic goiter include

Using certain drugs (such as amiodarone or lithium )
Eating certain foods in unusually large amounts (such as cassava, broccoli, cauliflower, and cabbage)

Sometimes a goiter forms temporarily during puberty, pregnancy, or menopause.
In people with simple, nontoxic goiter, the thyroid gland produces normal amounts of thyroid hormones, so people do not have an underactive thyroid (hypothyroidism) or an overactive thyroid (hyperthyroidism).