What is acromegaly caused by?

Acromegaly is caused by the excess production of growth hormone, which is typically the result of a benign tumor on the pituitary gland known as an adenoma. This overproduction of growth hormone leads to an increase in the growth of bones and soft tissues, resulting in the characteristic features of acromegaly, such as enlarged hands and feet, facial changes, and various systemic complications.

The condition is not associated with thyroid hormones, insulin, or parathyroid hormone deficiencies or excesses. Thyroid hormone deficiencies would lead to hypothyroidism, affecting metabolism rather than causing acromegaly. Excess insulin is associated with conditions like hyperinsulinism or diabetes, but plays no role in the pathophysiology of acromegaly. Insufficient parathyroid hormone leads to hypoparathyroidism, which is unrelated to growth hormone levels and their effects on bone growth and tissue development.

Thus, the correct choice highlights the fundamental cause of acromegaly, illustrating the pivotal role that growth hormone plays in this disorder.