What specialty should a patient with an adrenal lesion on CT (Computed Tomography) scan be referred to?

Referral for Adrenal Lesions on CT Scan

Patients with adrenal lesions found on CT scan should be referred to an endocrinologist as the primary specialist, with subsequent multidisciplinary involvement based on specific characteristics of the lesion. 1

Initial Evaluation and Referral Pathway

Primary Referral: Endocrinology

• Endocrinologists are the primary specialists for adrenal lesions as they can:
  • Coordinate the hormonal evaluation necessary for all adrenal masses
  • Determine if the lesion is functioning or non-functioning
  • Guide appropriate management based on hormonal status

Secondary Referrals Based on Specific Characteristics:

1. Surgical Evaluation (Urologist or Endocrine Surgeon)

   • Indicated for:
     • Lesions >4 cm in diameter
     • Irregular margins or heterogeneous appearance
     • High attenuation (>10 HU) on non-contrast CT
     • Poor contrast washout (<60% at 15 minutes)
     • Any hormone-producing tumor
     • Growth >5 mm/year on follow-up imaging 1

2. Oncology Referral

   • Indicated for:
     • Suspected adrenal malignancy (adrenocortical carcinoma)
     • Metastatic disease to the adrenal gland
     • History of prior malignancy with adrenal mass 2

Diagnostic Workup Before Referral

Imaging Characterization

• Non-contrast CT (to determine Hounsfield Units)
  • HU <10 indicates benign adenoma
  • HU >20 increases suspicion for malignancy 1
• Consider contrast-enhanced washout CT or chemical shift MRI for indeterminate lesions 2
• FDG-PET may be useful for distinguishing malignant from benign lesions, particularly in patients with history of cancer 2

Hormonal Evaluation

Every patient with an adrenal incidentaloma should have:

• 1-mg overnight dexamethasone suppression test (for cortisol)
• Plasma or 24-hour urinary metanephrines (for pheochromocytoma)
• Aldosterone-to-renin ratio (for primary aldosteronism) 1, 3

Management Algorithm

1. Benign-appearing adrenal adenomas (<4 cm, homogeneous, <10 HU)

   • Refer to endocrinology for hormonal evaluation
   • If non-functioning: No further imaging follow-up required 1
   • If hormone-producing: Refer to endocrine surgeon

2. Indeterminate adrenal masses (1-4 cm with atypical imaging)

   • Refer to endocrinology for hormonal evaluation
   • Consider additional imaging (contrast washout CT or MRI)
   • Follow-up imaging in 3-6 months 1

3. Suspicious adrenal masses (>4 cm, irregular, heterogeneous)

   • Urgent referral to endocrinology and surgical evaluation
   • Complete hormonal workup before any intervention
   • Rule out pheochromocytoma before any invasive procedure 2

Important Considerations

• Pheochromocytoma precautions: Always rule out pheochromocytoma before biopsy or surgery to prevent potentially fatal hypertensive crisis 2, 4
• History of malignancy: Patients with history of cancer require more aggressive evaluation as adrenal lesions are more likely to be malignant 2
• Bilateral adrenal masses: May indicate different pathology (metastases, congenital adrenal hyperplasia, infiltrative diseases) and require specialized evaluation 3

Common Pitfalls to Avoid

1. Failure to perform hormonal evaluation: Even radiologically benign-appearing lesions can be hormonally active 5
2. Direct referral for biopsy without hormonal testing: Can be catastrophic if the lesion is a pheochromocytoma 2, 4
3. Inadequate follow-up: Only 26-32% of adrenal incidentalomas receive appropriate workup and follow-up 5
4. Overlooking radiologist recommendations: Action is more likely to be taken when the reporting radiologist provides specific follow-up advice 5

By following this referral pathway, patients with adrenal lesions will receive appropriate evaluation and management, minimizing both unnecessary procedures for benign lesions and delays in treatment for clinically significant ones.