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. 2014 Jan 1;8(1):1–12. doi: 10.3941/jrcr.v8i1.1551

Table 4.

Comparison between adrenal and extra-adrenal myelolipomas

Adrenal Extra-adrenal
Incidence

  • -<1% of autopsy

  • -7–15% of incidental adrenal masses

  • -Very rare

  • -About 14% of all myelolipomas
Age predilection 6th–8th decades Younger patients may be also involved
Etiology Not quite understood
Multiplicity

  • -Unilateral

  • -Rarely bilateral (10%)

 Multiple lesions are extremely rare
Site Adrenal glands

  • -Presacral

  • -Retroperitoneal

  • -Other rare sites
Size Usually 2–10cm Usually 4–15cm
Gross pathology

  • -Pseudocapsule

  • -Fat and soft tissue
Hemorrhage In larger lesions (>10cm) Extremely rare
Calcification 20 %
usually due to hemorrhage		 Extremely rare
Microscopic picture Mature fat cells & megakaryocytes
Clinical Picture

  • -Usually asymptomatic

  • -10% causing vague symptoms

  • -Usually asymptomatic

  • -Symptoms according to location & size
Imaging key findings

  • -Fat: low attenuation in CT & high in both T1 & T2 WI

  • -Myeloid tissue: higher density, low signal on T1 WI, moderate on T2 WI, moderate enhancement
Differential diagnosis Adenoma

  • -According to location

  • -Extra-medullary hematopoiesis

  • -Lipoma/Liposarcoma
Prognosis Excellent Excellent
Indication for surgery

  • -Symptomatic lesions

  • -Larger tumors (risk of hemorrhage)

  • -Uncertainty of diagnosis

  • -Mass effect