Clinical History:
- A 40-year-old woman has experienced a weight gain of 6 kg, acne, and increased facial hair over the past 3 months. On physical examination her temperature is 36.9 C, pulse 80/minute, respirations 16/minute, and blood pressure 154/98 mm Hg. She is noted to have truncal obesity, a round face, acne of her face and upper chest, ecchymoses of her arms and legs, purplish abdominal striae, and hirsutism. Hyperpigmentation of the skin and proximal muscular weakness are not apparent. She had not been seeing a physician and was taking no medications prior to this visit to the physician.
- Why is the medication history important? This set of problems could be due to medication with corticosteroids (most common cause of Cushing syndrome). What laboratory tests should be ordered? A serum ACTH and a dexamethasone suppression test, should be done. The baseline ACTH was 20 pg/ml (normal 20-100). Following a single dose of dexamethasone, the plasma cortisol was 20 micrograms/dl (normal <5).
- Dexamethasone suppression test: for screening, a single dose of dexamethasone (a potent glucocorticoid that inhibits ACTH secretion) is given and the morning cortisol is measured. Failure to suppress with a single dose dexamethasone suppression test defines the abnormality as Cushing syndrome, but does not discriminate between pituitary dependent Cushing, an adrenal cortical neoplasm, or nonpituitary ACTH secretion. A high dose dexamethasone suppression test over a couple of days can be done; failure to suppress at the higher dose suggests an adrenal neoplasm or ectopic ACTH production.
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- A CT scan of the abdomen revealed a large retroperitoneal mass. Surgery was performed.
- What is the diagnosis? Where is the origin of this neoplasm, compared to case 4?
This is an adrenal cortical carcinoma associated with Cushing
syndrome as a consequence of glucocorticoid production by the carcinoma. It
arises in the adrenal cortex, not the medulla, as pheochromocytomas do.
- What do such lesions secrete?
The majority of adrenal carcinomas actually do secrete hormones, mostly corticosteroids and their precursors. Some secrete androgenic or estrogenic hormones, leading to virilization or femininization. Adrenal carcinomas very rarely produce aldosterone.
- What are the signs of malignancy?
Reliable indications of malignancy include metastases, invasion of vasculature or adjacent tissue, spindle cells, and numerous mitotic figures. Tumor size >5 cm is also an indicator.
- What are the most common sites of metastatic disease?
Regional lymph nodes, liver, and lung are the most common sites.
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