What is the procedure for performing an adrenal gland biopsy?

Adrenal Gland Biopsy Procedure

CT-guided percutaneous biopsy is the preferred approach for adrenal gland sampling, with the posterior paravertebral approach offering the safest and most effective technique for most patients. 1

Indications for Adrenal Biopsy

• Adrenal biopsy should not be performed routinely for the work-up of adrenal incidentalomas 1
• Biopsy is most appropriate in patients with:
  • History of malignancy with suspected metastatic disease to the adrenal gland 1
  • Indeterminate adrenal masses that remain equivocal after non-invasive imaging techniques (CT, MRI, PET) 1
• Biopsy is better suited for patients with high risk for malignant lesions and is most useful when noninvasive studies have negative results 1

Pre-Biopsy Evaluation

• CRITICAL: Exclude pheochromocytoma before any adrenal biopsy 1, 2
  • Several deaths have been reported after adrenal biopsies of undiagnosed pheochromocytomas 1
  • Screen with plasma or 24-hour urinary metanephrines in all patients with adrenal masses >10 HU on non-contrast CT or with symptoms of catecholamine excess 1, 2
• Complete hormonal evaluation should be performed before considering biopsy:
  • Cortisol secretion assessment (1 mg overnight dexamethasone suppression test) 1, 2
  • Aldosterone-to-renin ratio in patients with hypertension and/or hypokalemia 1, 2
  • Androgen excess testing in cases with clinical signs of virilization 1, 2

Biopsy Technique

CT-Guided Percutaneous Approach

• Posterior paravertebral approach is preferred for most adrenal biopsies 1, 3
  • Advantages: Avoids traversing major organs, minimizes risk of complications 3
  • Can be enhanced with hydrodissection technique (saline injection to expand the paravertebral space) 3
• Alternative approaches include:
  • Anterior transhepatic/transpancreatic approach 3
  • Lateral transhepatic/transplenic approach 3
  • Posterior transpulmonary/transpleural approach 3

Advanced Guidance Techniques

• C-arm cone-beam CT with stereotactic needle guidance shows promise for difficult-to-access adrenal masses 4
  • Technical success rate of 100% reported in one study 4
  • Particularly useful for hard-to-reach anatomical locations 4
• EUS-guided FNA (endoscopic ultrasound-guided fine needle aspiration) is effective for left adrenal gland biopsies 1
  • Sensitivity and negative predictive value of at least 86% and 70%, respectively 1
  • Can be performed during the same session as mediastinal staging in lung cancer patients 1

Diagnostic Yield and Accuracy

• Adequate tissue samples are obtained in 81-96% of cases 1, 5
• Accuracy for malignant lesions is 96-100% when sufficient material is obtained 1
• Biopsy interpretation is more difficult in benign processes 1
• Overall accuracy to differentiate benign from malignant disease is approximately 85-95% 5, 4

Complications

• Complication rates range from 8-12% 1
• Potential complications include:
  • Bleeding/hemorrhage 1, 3
  • Pneumothorax 1, 3
  • Infection 1
  • Tumor seeding along needle track (rare) 1
  • Hypertensive crisis (in undiagnosed pheochromocytomas) 2
• Minor bleeding occurs in approximately 3.3% of cases 4

Special Considerations

• Dedicated adrenal imaging with CT or MRI should be performed before considering biopsy to avoid unnecessary procedures 6
  • The introduction of dedicated adrenal CT and MRI has markedly reduced the number of adrenal adenomas requiring biopsy 6
• For left adrenal gland biopsies in patients with lung cancer, EUS-FNA is a reasonable alternative to percutaneous approaches 1
• Adrenal biopsy should be reserved for cases in which noninvasive techniques are equivocal 1