What is the management approach for adrenal myelolipoma?

Management of Adrenal Myelolipoma

Adrenal myelolipomas do not require any follow-up imaging or functional testing after initial characterization, regardless of size. 1, 2

Initial Diagnostic Approach

Radiologic Confirmation

• Myelolipomas are definitively diagnosed by their characteristic appearance on imaging showing macroscopic fat content 1, 2
• Non-contrast CT demonstrating fat density (negative Hounsfield units) with heterogeneous appearance due to admixed hematopoietic elements confirms the diagnosis 2
• No biopsy is needed or recommended, as imaging characteristics are pathognomonic 2

Hormonal Evaluation

• Initial hormonal screening should still be performed to exclude the rare association with functional adrenal disorders 3
• Screen with 1 mg overnight dexamethasone suppression test, plasma/urinary metanephrines, and aldosterone-to-renin ratio if hypertensive 2, 4
• Myelolipomas themselves are biochemically inactive, but may coexist with other endocrine abnormalities 3, 5

Management Algorithm Based on Size and Symptoms

Small Asymptomatic Myelolipomas (<4 cm)

• No further imaging or functional testing required after initial characterization 1, 2
• This represents a strong recommendation with moderate quality evidence from the 2023 CUA/AUA guidelines 1
• Discharge from follow-up is appropriate 2

Large Asymptomatic Myelolipomas (≥4 cm)

• Conservative management is acceptable for asymptomatic lesions, even when large 3, 6
• The traditional 4 cm cutoff for repeat imaging does not apply to confirmed myelolipomas, as they are benign regardless of size 1, 2
• Some literature suggests considering surgery for lesions ≥6-7 cm due to risk of spontaneous hemorrhage or rupture, though this remains controversial 6, 7

Symptomatic Myelolipomas (Any Size)

• Surgical excision is indicated for symptomatic lesions 3, 6, 8, 7
• Common symptoms include abdominal/flank pain, increasing abdominal girth, or palpable mass 3, 6, 8
• Laparoscopic adrenalectomy is the preferred approach when feasible 6, 7
• Adrenal-sparing surgery should be attempted when possible to avoid lifelong steroid replacement, particularly for bilateral lesions 3

Indeterminate Cases

• If imaging cannot definitively exclude liposarcoma or other malignancy (irregular margins, soft tissue components beyond expected hematopoietic elements), surgical excision is warranted 3
• This scenario is rare, as typical myelolipomas have characteristic fat-containing appearance 2

Critical Pitfalls to Avoid

• Do not subject patients with confirmed myelolipomas to repeated imaging surveillance - this increases radiation exposure, anxiety, and costs without clinical benefit 1, 2, 4
• Do not perform adrenal biopsy - imaging diagnosis is sufficient and biopsy carries unnecessary risks 2, 4
• Do not assume all fat-containing adrenal masses are myelolipomas - consider adrenocortical carcinoma with fatty degeneration or liposarcoma if imaging features are atypical 3
• For bilateral giant myelolipomas requiring surgery, preserve as much adrenal tissue as possible to prevent adrenal insufficiency 3

Special Considerations

• Myelolipomas may be associated with obesity, hypertension, and rarely with Cushing's disease, Addison's disease, or hyperaldosteronism 3, 5
• Bilateral myelolipomas are uncommon but reported 3, 5
• Giant myelolipomas (>10 cm) have been documented, with the largest reported weighing 6,000 grams 8
• No malignant transformation has ever been reported - these are definitively benign lesions 3, 6, 7