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Zorluk: Çok zorDiagnostic Workup and Test Sequencing

A 52-year-old man undergoes an unenhanced computed tomography (CT) scan of the abdomen and pelvis to evaluate suspected nephrolithiasis after recently passing a calcium oxalate stone. The scan reveals an incidental 4.6-cm, well-circumscribed left adrenal mass with an unenhanced attenuation of 28 Hounsfield units. The right adrenal gland is normal. The patient is completely asymptomatic. He has no history of hypertension, palpitations, headaches, or weight changes. He takes no medications. Vital signs are temperature 37.1°C (98.8°F), blood pressure 118/76 mm Hg, heart rate 72/min, and respiratory rate 14/min. Physical examination reveals no abdominal bruits, purple striae, central adiposity, or abnormal fat distribution. Serum potassium is 4.3 mEq/L and serum creatinine is 0.9 mg/dL. Which of the following is the most appropriate next step in the diagnostic workup?

  1. A
    Measurement of plasma fractionated metanephrines, 1-mg overnight dexamethasone suppression test, and plasma aldosterone-to-renin ratio
  2. B
    CT-guided core needle biopsy of the left adrenal mass
  3. C
    Referral for immediate laparoscopic adrenalectomy
  4. Measurement of plasma fractionated metanephrines and a 1-mg overnight dexamethasone suppression testCevap
  5. E
    18F-FDG Positron emission tomography (PET) scan of the body

Cevap

The most appropriate next step is the measurement of plasma fractionated metanephrines and a 1-mg overnight dexamethasone suppression test.
The correct answer identifies the fundamental rule of adrenal incidentaloma management: all patients must undergo biochemical screening for pheochromocytoma (using plasma fractionated metanephrines) and autonomous cortisol secretion (using a 1-mg overnight dexamethasone suppression test) before any invasive procedures, advanced staging imaging, or surgical interventions. Because this patient is normotensive and normokalemic, testing for primary hyperaldosteronism (aldosterone-to-renin ratio) is not indicated.

Adım Adım Çözüm

1
Identify the clinical presentation and significance of the imaging findings.
An asymptomatic, normotensive, normokalemic patient is found to have an incidental 4.6-cm, lipid-poor (28 Hounsfield units) adrenal mass.
This presentation defines an adrenal incidentaloma with high-risk imaging features (size >4 cm and attenuation >10 Hounsfield units suggest a higher risk for adrenocortical carcinoma or pheochromocytoma).
2
Determine the required universal biochemical screening for all adrenal incidentalomas.
All patients require screening for pheochromocytoma (using plasma free or 24-hour urine fractionated metanephrines) and autonomous cortisol secretion (using a 1-mg overnight dexamethasone suppression test).
Functional tumors must be identified to prevent catastrophic perioperative complications (e.g., hypertensive crisis or post-operative adrenal insufficiency) if surgery is pursued.
3
Evaluate the need for additional targeted biochemical screening.
Screening for primary hyperaldosteronism is determined to be unnecessary.
The patient is completely normotensive and normokalemic; therefore, an aldosterone-to-renin ratio is not clinically indicated.
4
Assess the correct sequence regarding invasive procedures or definitive surgery.
Surgical referral or biopsy is postponed until biochemical results are available.
Even with high-risk imaging features that will likely ultimately necessitate resection, biochemical clearance MUST precede any invasive steps to ensure patient safety.

Anahtar Kavram

All adrenal incidentalomas require initial biochemical screening for pheochromocytoma and autonomous cortisol secretion prior to invasive procedures; screening for primary hyperaldosteronism is reserved only for patients with hypertension or hypokalemia.
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Diagnostic Workup and Test Sequencing

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