"Incidentaloma" in a Middle-aged Woman

By RONALD N. RUBIN, MD—Series Editor
Volume 43 - Issue 7 - July 2003
A 45-year-old woman presents with multiple injuries she sustained during a skiing accident. She has fractures of her right arm and 3 ribs, as well as numerous contusions. An abdominal CT scan shows no hemorrhage or other traumarelated findings; however, a 6.7-cm left adrenal mass is detected.HISTORY
Before the accident, the patient was healthy. She has no significant medical conditions; her only medications are vitamin supplements and an oral contraceptive. She has no history of back pain or hematuria.PHYSICAL EXAMINATION
Body habitus is normal; no skin lesions or striae; no hirsutism. Heart rate is 92 beats per minute; respiration rate, 16 breaths per minute; and blood pressure, 118/78 mm Hg. Heart and lungs are normal. Abdomen and flanks are soft and nontender, without palpable masses.LABORATORY RESULTS
Results of a hemogram, serum chemistry panel, and urinalysis are normal.Which of the following is the optimal strategy for evaluation of the adrenal mass?A. Order a chest CT scan, measure serum cortisol level at 4 PM, and repeat the abdominal imaging in 3 months.B. Order a 1-mg dexamethasone( suppression test, measurement of plasma free metanephrines, and a surgical consultation.C. Measure plasma renin and aldosterone levels, measure serum cortisol level at 8 AM, and repeat abdominal imaging in 6 months.D. Measure serum testosterone level, measure fasting plasma epinephrine and norepinephrine( levels, and order a surgical consultation.CORRECT ANSWER: B
This patient has what is commonly referred to as an “incidentaloma”— a clinically inapparent adrenal mass that is discovered inadvertently during diagnostic testing or treatment of a condition unrelated to adrenal disease.1Although precise incidence figures are not available, technologic improvements in and more frequent use of imaging techniques such as CT and MRI have clearly resulted in an increase in incidentalomas. The incidence at autopsy is 2.1%.2Incidentalomas may represent potentially fatal lesions (adrenal cortical carcinomas) or lesions associated with significant morbidity (hormonally active adrenal tumors, such as pheochromocytomas, aldosteromas, or those that result in subclinical hypercortisolism); thus, the clinical evaluation focuses on the exclusion of these entities. When an adrenal mass is detected as an incidental finding, the key concerns are:
  • Is the lesion a malignant adrenocortical carcinoma or a metastasis from another source?
  • Is there evidence of adrenal hyperfunction?
Exclusion of malignancy. Benign nonfunctioning adrenal adenomas are rarely larger than 4 to 6 cm in diameter. Among patients with lesions larger than 6 cm, the incidence of cancer is 25%.1Thus, because this patient’s adrenal mass is 6.7 cm, surgical removal is indicated (choices B and D). Waiting 3 months (choice A) or 6 months (choice C) is too conservative an approach for a lesion of this size. However, before the patient undergoes surgery, biochemical evaluation for Cushing syndrome and pheochromocytoma is necessary because both disorders require specific perioperative management. If the urinary free cortisol level is elevated, the patient will be at risk for hypoadrenalism after the mass is removed and she will require stress glucocorticoids until her postoperative status can be established. Elevated urinary catecholamine or catecholamine metabolite levels—which indicate pheochromocytoma— signal the need for volume repletion and administration of α-adrenergic blockers before surgery and expert perioperative anesthesia care.Exclusion of hormonally active tumors. Depending on the clinical presentation, the biochemical screening evaluation may include:
  • Measurement of urinary free cortisol level.
  • A 1-mg overnight dexamethasone suppression test.
  • Measurement of plasma renin and aldosterone levels.
  • Measurement of plasma free metanephrine levels.
  • Measurement of urinary catecholamine and catecholamine metabolite levels.
  • Measurement of serum potassium level.
  • Measurement of plasma testosterone and 17-ketosteroid levels (in women).
Blood pressure and results of a chemistry panel are normal in this patient, which makes an aldosteroma unlikely. Adrenal hypersecretion of androgens is not common in adults; moreover, this patient has no clinical stigmata of the condition. Thus, measurement of serum testosterone levels (choice D) is not appropriate. In this patient, the most appropriate screening studies are those for pheochromocytoma and subclinical hypercortisolism. A recent review suggests that a 1-mg dexamethasone suppression test and measurement of plasma free metanephrines (choice B) are the optimal screening tests for subclinical hypercortisolism and pheochromocytoma, respectively.1 The 1-mg dexamethasone test is superior to random measurement of serum cortisol levels (choices A and C) because cortisol levels fluctuate throughout the day and may be normal in patients with subclinical hypercortisolism. Measurement of plasma free metanephrine levels adds sensitivity and specificity to an evaluation for pheochromocytoma and is superior to catecholamine measurement alone (choice D).Outcome of this case. The resected mass was a lipoma.
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