To whom should a primary care provider refer a patient with adrenal lipomatous lesions?

Referral Pathway for Patients with Adrenal Lipomatous Lesions

Primary care providers should refer patients with adrenal lipomatous lesions to an endocrinologist for initial evaluation, with subsequent referral to an endocrine surgeon or urologist if surgical intervention is indicated. 1

Initial Assessment and Referral Decision

The management of adrenal lipomatous lesions depends on several key factors:

1. Size of the lesion:

   • Lesions <4 cm with benign imaging features (HU ≤10) generally require no further follow-up 1
   • Lesions ≥4 cm or those with concerning features require specialist evaluation 1, 2

2. Imaging characteristics:

   • Lipomatous lesions typically show characteristic fat density on CT/MRI 1
   • Benign adenomas have Hounsfield Units (HU) <10 on non-contrast CT 1
   • Myelolipomas show characteristic fat density with areas of soft tissue 1

3. Hormonal status:

   • All adrenal masses require hormonal evaluation regardless of appearance 1
   • Hormone-secreting lesions require specialized management 1

Referral Algorithm

Step 1: Initial Referral to Endocrinologist

The endocrinologist will conduct comprehensive hormonal evaluation including:

• 1mg overnight dexamethasone suppression test for cortisol assessment 1
• Plasma free metanephrines or 24-hour urinary fractionated metanephrines 1
• Aldosterone-to-renin ratio in patients with hypertension/hypokalemia 1
• Sex hormone evaluation if clinically indicated 1

Step 2: Secondary Referral Based on Findings

• Refer to Endocrine Surgeon or Urologist if:

  • Lesion >4 cm with inhomogeneous appearance or HU >20 1
  • Any lesion >6 cm regardless of appearance 1
  • Biochemically confirmed hormone-producing tumor 1
  • Growth >5 mm/year on follow-up imaging 1
  • Symptomatic lesions 2

• Continue Endocrinology Follow-up if:

  • Lesion <4 cm with benign features (HU ≤10) 1
  • Non-functioning lesion without concerning radiologic features 1

Special Considerations for Lipomatous Adrenal Lesions

Adrenal lipomatous tumors include several subtypes:

• Myelolipomas (most common, ~3% of primary adrenal tumors) 3
• Lipomas 3
• Teratomas 3
• Angiomyolipomas 3
• Rare: liposarcoma 4

Important Caveats

• Diagnostic pitfall: Some adrenocortical neoplasms may contain areas of myelolipomatous or lipomatous metaplasia, potentially leading to misdiagnosis as benign myelolipoma on imaging 5

• Malignancy risk: While most lipomatous adrenal tumors are benign 2, careful evaluation is necessary as rare malignant variants like liposarcoma exist 4

• Calcification: Approximately one-third of adrenal lipomatous tumors may contain calcification or bone, which should not be automatically considered a sign of malignancy 4

• Bilateral lesions: Approximately 40 cases of bilateral myelolipomas have been reported, requiring careful evaluation 3

• Hormonal activity: While most lipomatous adrenal tumors are non-functional 3, hormonal evaluation is still essential to rule out subtle hormone production 1

By following this referral pathway, primary care providers can ensure appropriate specialist evaluation and management for patients with adrenal lipomatous lesions, optimizing outcomes while avoiding unnecessary interventions.