Ectopic adrenal myelolipoma at the hepatic-adrenal interface mimicking hepatic angiomyolipoma: A case report

BACKGROUNDMyelolipoma is an extremely rare benign tumor composed of mature adipose tissue and hematopoietic elements.Its non-specific clinical presentation and imaging characteristics make preoperative diagnosis difficult, and it may be misdiagnosed as other fat-containing hepatic tumors, particularly hepatic angiomyolipoma.The tissue origin and pathogenesis of hepatic myelolipoma remain unclear.This report presents a rare case of an ectopic adrenal myelolipoma located at the hepatic-adrenal interface with liver involvement.CASE SUMMARY A 61-year-old woman presented with intermittent right upper abdominal pain for more than 2 months.Contrast-enhanced computed tomography showed a 6.2 cm × 4.2 cm fat-containing mass in the right posterior liver adjacent to the right adrenal gland.Magnetic resonance imaging demonstrated marked signal loss on opposedphase images, mild delayed enhancement, and hypointensity in the hepatobiliary phase.Hepatic angiomyolipoma was suspected preoperatively.Given the patient's symptoms and the lesion's size (> 6 cm), laparoscopic local resection of the right posterior liver was performed.Histopathological examination showed mature adipose and hematopoietic tissues within the capsule, focal adrenal tissue immediately inside the capsule, and hepatic tissue outside the capsule.These findings supported a diagnosis of ectopic adrenal myelolipoma with liver involvement.The patient was discharged on postoperative day 7.During 19 months of follow-up, her abdominal pain improved, with no documented recurrence or postoperative complications.CONCLUSION Ectopic adrenal myelolipoma should be considered in the differential diagnosis of fat-containing lesions at the hepatic-adrenal interface.4 / 17