Which adrenal lesion can cause Cushing's syndrome via cortisol secretion?

• A. Cortisol-secreting adrenal adenoma
• B. Aldosterone-secreting adrenal adenoma
• C. Pheochromocytoma
• D. Adrenal cortical hyperplasia

Answer: (A)

Cushing's syndrome from cortisol excess happens when cortisol is produced autonomously by adrenal tissue. A cortisol-secreting adrenal adenoma fits this best because it directly makes cortisol independent of pituitary ACTH, leading to the classic features of Cushing's: central obesity, rounded moon face, proximal muscle weakness, glucose intolerance, hypertension, and striae.

The other lesions don’t produce the cortisol-driven syndrome in the same way. An aldosterone-secreting adrenal adenoma causes primary hyperaldosteronism, with hypertension and low potassium, not the cortisol-signature features. Pheochromocytoma secretes catecholamines and presents with episodic hypertension, palpitations, and sweating. Adrenal cortical hyperplasia can cause cortisol excess in some contexts, but the most straightforward, classic example of causing Cushing's via cortisol secretion is a cortisol-producing adrenal adenoma.