Pituitary Disorders USMLE Step 1 Practice Question
A 38-year-old woman presents with progressive bifrontal headache and bitemporal hemianopsia. Vital signs show BP 158/94 mmHg, HR 88/min, RR 16/min, Temp 37.2°C. She denies recent weight gain. Labs reveal ACTH 78 pg/mL, 24-hour urinary cortisol 180 mcg/24hr, low-normal DHEA-S, and normal TSH. MRI demonstrates a 6-mm sellar mass with suprasellar extension. Which diagnosis best explains these findings?
Answer choices
- AIatrogenic Cushing syndrome from glucocorticoid use
- BAdrenocorticotropic hormone-independent macronodular adrenal hyperplasia
- CEctopic ACTH secretion from lung carcinoma
- DCushing syndrome due to ACTH-secreting pituitary adenomaCorrect answer
- EPrimary adrenal adenoma
- FCushing syndrome due to corticotropin-releasing hormone-secreting hypothalamic hamartoma
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