Which of the following is an endocrine disorder characterized by goiter, exophthalmos, and thyrotoxicosis?

Acromegaly is a disorder caused by excess growth hormone, typically due to a pituitary tumor. It primarily leads to abnormal growth of bones and tissues, particularly in the face, hands, and feet, rather than the thyroid-related symptoms seen in Graves' disease. Thus, it does not present with goiter, exophthalmos, or thyrotoxicosis.

Cushing's disease results from prolonged exposure to elevated cortisol levels, usually due to a pituitary tumor. Symptoms include weight gain, hypertension, and skin changes, but it does not involve the thyroid gland or present with the classic signs of hyperthyroidism, such as goiter or exophthalmos.

Hashimoto's thyroiditis is an autoimmune disorder that leads to hypothyroidism, characterized by chronic inflammation of the thyroid gland. While it can cause an enlarged thyroid (goiter), it does not cause thyrotoxicosis or exophthalmos, which are characteristic of hyperthyroidism, specifically found in Graves' disease.

Myxedema refers to severe hypothyroidism, often resulting from untreated Hashimoto's thyroiditis. It presents with symptoms such as swelling, fatigue, and sensitivity to cold but is contrary to the symptoms of hyperthyroidism associated with Graves' disease, including goiter, exophthalmos, and thyrotoxicosis.