Home Education AUAUniversity Education Products & Resources Pathology for Urologists Andrenal Gland Adrenal Myelolipoma

Adrenal Myelolipoma

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  • Tumorlike lesion of adrenal land composed of fat and bone marrow elements.
  • Asymptomatic, patients usually in their 50s, rarely may present with flank pain and abdominal mass.
  • Can also occur in the retroperitoneum.
  • Gross: Non-encapsulated circumscribed bright yellow to white-tan, size considerably vary (image A).

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  • Histology:
    • Presence of mature fat mixed with bone marrow elements (e.g. megakaryocytes [large multinucleated cell], myeloid cells and immature nucleated red blood cells [small round very dark nuclei, like "small bowling balls" and usually clusters together) (image B), (image C), & (image D).
    • Necrosis, hemorrhage and calcifications particularly with larger tumor.
  • Benign course.