Clusters of thyroid tissue that exist independently within the thyroid gland are referred to as autonomous nodules. These self-contained nodules have the ability to produce an excessive quantity of thyroid hormone, leading to a state of hyperthyroidism. This condition arises when the thyroid gland becomes overactive due to the increased production and release of thyroid hormones by these autonomous nodules. It is important to monitor and manage these nodules appropriately to regulate thyroid hormone levels and prevent potential complications associated with hyperthyroidism.