Bilateral adrenal myelolipoma.

Myelolipomas are rare benign tumors often found incidentally due, in the majority of cases, to the fact that they are asymptomatic. The incidence of adrenal myelolipomas at autopsy is low (0.2%). These tumors are made up of fat and hematopoietic cells. Their origin is unclear and different theories have been put forward, including development from rests of mesenchymal stem cells, embolism of bone marrow, extramedullary hematopoiesis and, according to the most widely accepted theory, metaplasia of the reticuloendothelial cells of blood capillaries. Due to their uncertain etiology and low frequency, management of adrenal myelolipomas is usually individualized and carried out depending on the protocols of each center. The development of improved imaging techniques has increased their diagnosis in routine clinical practice. Thus, they have been included in the heterogeneous group of 'incidentalomas' of the adrenal gland.