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Zorluk: ZorDiagnostic Workup and Test Sequencing

A 61-year-old woman is evaluated in the clinic after an emergency department visit two days ago for a minor mechanical fall. During that visit, a non-contrast CT scan of the abdomen and pelvis was performed to evaluate for suspected rib or solid organ injury. The scan showed no traumatic injuries, but an incidental 2.8-cm mass was identified in the left adrenal gland. The mass is well-circumscribed and homogeneous, with an attenuation of 4 Hounsfield units. The patient's medical history is significant for estrogen receptor-positive breast cancer treated with a lumpectomy and radiation therapy six years ago; she has been in remission since. She currently feels well and reports no abdominal pain, palpitations, headaches, or unexplained weight changes. Blood pressure is 126/82 mmHg, and heart rate is 72/min. Physical examination reveals no abdominal tenderness, striae, or palpable masses. Which of the following is the most appropriate next step in the diagnostic workup of this patient's adrenal mass?

  1. Measurement of plasma free metanephrines and an overnight 1-mg dexamethasone suppression testCevap
  2. B
    CT-guided fine-needle aspiration of the adrenal mass
  3. C
    Reassurance and a repeat non-contrast CT scan of the abdomen in 12 months
  4. D
    Whole-body positron emission tomography (PET) scan
  5. E
    Referral for laparoscopic left adrenalectomy

Cevap

Measurement of plasma free metanephrines and an overnight 1-mg dexamethasone suppression test
The correct sequence for evaluating a newly discovered adrenal incidentaloma involves two distinct pathways: radiologic evaluation to assess malignancy risk and biochemical evaluation to assess functional status. Radiologically, this mass is well-circumscribed, homogeneous, and has an attenuation of <10 Hounsfield units (HU), which confidently identifies it as a benign, lipid-rich adenoma, effectively ruling out metastasis from her prior breast cancer. Despite the benign imaging appearance, all adrenal incidentalomas must be evaluated for subclinical hormone hypersecretion. The standard initial workup includes an overnight 1-mg dexamethasone suppression test (to screen for autonomous cortisol secretion) and measurement of plasma free metanephrines or 24-hour urine fractionated metanephrines (to screen for pheochromocytoma). Since her blood pressure is normal, screening for primary hyperaldosteronism with a plasma aldosterone-to-renin ratio is not indicated.

Adım Adım Çözüm

1
Analyze the imaging characteristics of the incidentaloma.
The mass is 2.8 cm, homogeneous, and has an attenuation of 4 Hounsfield units (HU).
HU < 10 is diagnostic of a lipid-rich, benign adrenal adenoma, which makes a metastasis from her prior breast cancer highly unlikely.
2
Determine the required evaluation for all newly discovered adrenal incidentalomas.
All patients require biochemical testing to evaluate for functional status, regardless of the presence or absence of symptoms.
Subclinical hormone secretion (especially cortisol and catecholamines) is common and alters management.
3
Select the appropriate biochemical screening tests.
Plasma free metanephrines (or 24-hour urine fractionated metanephrines) and a 1-mg overnight dexamethasone suppression test.
These tests screen for pheochromocytoma and autonomous cortisol secretion, respectively. (Aldosterone/renin screening is only indicated if the patient has hypertension or hypokalemia).

Anahtar Kavram

Diagnostic sequencing for adrenal incidentalomas requires biochemical evaluation for hormone hypersecretion in all patients prior to any invasive procedures, even when imaging suggests a benign etiology.
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Diagnostic Workup and Test Sequencing

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