Cushing Syndrome Moon Face

A 39-year-old woman presents with a 2-year history of progressive weight gain, easy bruising, and new-onset hypertension and diabetes. On examination, the structure marked **A** is noted—a rounded, plethoric face with marked facial fullness and bilateral malar redness. She also has wide violaceous abdominal striae (>1 cm), proximal myopathy, and a dorsocervical fat pad. Her 24-hour urine free cortisol is 380 mcg/24h (normal <50), late-night salivary cortisol is 8.2 ng/mL, and the 1 mg overnight dexamethasone suppression test shows a morning cortisol of 14 mcg/dL (not suppressed). Which of the following best describes the pathophysiological basis for the appearance marked **A** in this patient?