Which disease is characterized by chronic lymphocytic thyroiditis?

Hashimoto's thyroiditis is characterized by chronic lymphocytic thyroiditis, where the thyroid gland is attacked by the body's immune system, leading to inflammation and damage. This autoimmune condition results in the gradual destruction of thyroid tissue, causing hypothyroidism in many cases. The presence of lymphocytic infiltration is a hallmark of this disease, which sets it apart from other thyroid disorders.

Graves' disease, while also an autoimmune condition, is characterized by hyperthyroidism and the presence of thyrotoxic symptoms due to excessive production of thyroid hormones, rather than chronic lymphocytic inflammation. Hyperthyroidism itself refers to the overproduction of thyroid hormones, which can occur due to various causes, but does not specifically relate to the chronic inflammatory aspect of lymphocytic infiltration seen in Hashimoto's thyroiditis. Toxic goiter typically refers to a goiter producing excess thyroid hormones, often linked to other conditions but not primarily identified by lymphocytic thyroiditis like Hashimoto's.

Therefore, the distinct characteristic of chronic lymphocytic thyroiditis clearly identifies it with Hashimoto's thyroiditis, making it the correct answer.