Adrenal myelolipoma:
Adrenal myelolipoma was first described by Arnold as “adrenal lipoma” in 1866, but it was Gierke in 1905 who described the myeloid component. The term “myelolipoma” was coined by Oberling in 1929. Most of the early literature describes it as an incidental autopsy finding or as occasional case reports. In the last two decades, widespread use of imaging studies has resulted in a dramatic increase in the incidentally discovered adrenal masses. As a result, endocrine associations across the world are issuing successive guidelines for the management of adrenal incidentalomas (AIs).
It is a rare, benign tumor of the adrenal gland of unknown etiology. The tumor usually shows varying degrees of lipomatous as well as myeloid tissue. Typically, there is lipid tissue containing an active bone marrow component, showing normal trilineage hematopoiesis but with markedly increased number of megakaryocytes. It is categorized as Type I: Predominantly lipomatous tissue with minimal hematopoietic elements and Type II: Hematopoietic elements predominate. Myelolipomas originate in the adrenal cortex and their surfaces consist of a pseudocapsule of compressed zona glomerulosa and fasciculate tissue.