Adrenal myelolipomas.

Adrenal myelolipomas are benign, lipomatous tumours with elements of myeloid cells, most of which present as adrenal incidentalomas and comprise 3·3-6·5% of all adrenal masses. Adrenal myelolipomas are usually unilateral (in 95% of cases), variable in size, most often found during midlife, and affect both sexes almost equally. On imaging, adrenal myelolipomas show pathognomonic imaging features consistent with the presence of macroscopic fat. Large adrenal myelolipomas can cause symptoms of mass effect, and can occasionally be complicated by haemorrhage. In the event of a concomitant adrenal cortical adenoma or hyperplasia, adrenal hormone excess might be detected in patients with adrenal myelolipoma. Patients with congenital adrenal hyperplasia exhibit a higher prevalence of adrenal myelolipomas than other patient groups, and are at risk of developing large and bilateral lesions. This Review discusses the pathogenesis, clinical presentation, and management of adrenal myelolipomas.