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Zorluk: ZorInterpreting Imaging Results

A 59-year-old woman is evaluated in the emergency department for severe, colicky left flank pain radiating to the left groin. Her medical history is notable for essential hypertension, for which she takes amlodipine. Her blood pressure is 144/88 mmHg, pulse is 86/min, and temperature is 37.0°C (98.6°F). Laboratory studies show a serum potassium of 4.2 mEq/L and an otherwise normal basic metabolic panel.

A non-contrast CT scan of the abdomen and pelvis demonstrates a 4-mm radiopaque calculus in the left distal ureter. Incidentally, the radiologist notes a 3.2-cm, well-circumscribed, homogeneous mass in the right adrenal gland. The mass has an unenhanced attenuation value of 8 Hounsfield units (HU). The patient's pain is well controlled with intravenous ketorolac, and she is tolerating oral hydration.

Regarding the incidental adrenal finding, which of the following is the most appropriate next step in management?

  1. Assess plasma free metanephrines, aldosterone-to-renin ratio, and perform a 1-mg dexamethasone suppression testCevap
  2. B
    Order a dedicated adrenal CT with contrast washout protocol
  3. C
    Schedule a CT-guided percutaneous core biopsy of the right adrenal mass
  4. D
    Measure plasma renin activity and aldosterone levels only if serum potassium falls below 3.5 mEq/L
  5. E
    Discharge with reassurance and schedule a repeat non-contrast CT scan in 12 months

Cevap

The most appropriate next step is to assess plasma free metanephrines, the aldosterone-to-renin ratio, and perform a 1-mg dexamethasone suppression test.
The correct action recognizes that while the imaging characteristics (homogeneous, well-circumscribed, < 10 HU) definitively identify the mass as a benign adrenal adenoma, its functional status remains unknown. Clinical guidelines require that all adrenal incidentalomas be evaluated with a 1-mg overnight dexamethasone suppression test (to rule out subclinical Cushing syndrome) and plasma free metanephrines or 24-hour urine fractionated metanephrines (to rule out pheochromocytoma). Because this patient has a history of hypertension, an aldosterone-to-renin ratio is also indicated to screen for primary hyperaldosteronism. No further imaging is needed because the low Hounsfield unit (HU) value (< 10) confirms the mass is lipid-rich and benign.

Adım Adım Çözüm

1
Interpret the incidental imaging findings.
The CT reveals a 3.2-cm right adrenal mass with an unenhanced attenuation of 8 HU.
An unenhanced attenuation value of < 10 HU on CT is highly specific for a lipid-rich, benign adrenal adenoma, effectively ruling out malignancy or metastasis.
2
Determine the need for further radiographic evaluation.
No further imaging (such as contrast washout CT or MRI) is required.
The diagnosis of a radiographically benign adenoma is already established by the low Hounsfield unit value.
3
Evaluate the functional status of the adrenal mass.
Biochemical screening for hormone hypersecretion must be ordered.
All adrenal incidentalomas, regardless of benign imaging features, must be evaluated for subclinical hormone production (pheochromocytoma, Cushing syndrome, and primary hyperaldosteronism in hypertensive patients).

Anahtar Kavram

Adrenal incidentalomas with an unenhanced CT attenuation < 10 HU are definitively benign adenomas requiring no further imaging, but all must undergo biochemical evaluation for hormone hypersecretion.
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Interpreting Imaging Results

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