Giant extra-adrenal myelolipoma.

Myelolipomas are rare, benign tumors composed in varying proportions of adipose tissue and hematopoietic cells. Myelolipomas are typically found in the adrenal gland, but uncommon cases of extra-adrenal sites have been reported, primarily presacrally. Extra-adrenal myelolipomas must be distinguished from masses of extramedullary hematopoiesis, which are also composed of hematopoietic elements but are associated with anemia and marked bone marrow hyperplasia. Also, if the distinction between extra-adrenal myelolipomas and malignant tumors such as liposarcoma were made before surgery, an invasive procedure might be avoided. We report the case of an extremely large, asymptomatic, perirenal myelolipoma in a 66-year-old diabetic woman. We also review the literature on extra-adrenal myelolipomas.