[Adrenal myelolipoma: two case reports].

We report 2 cases of adrenal myelolipoma which were suspected preoperatively and confirmed by surgical resection. As with most cases previously reported, the lesions were found in obese, middle-aged persons. Laboratory tests of adrenal function revealed values within the normal level. Excretory urography showed radiolucent masses in the suprarenal area displacing the kidney inferiorly. Computerized tomography revealed well-defined masses consisting of fat density areas and higher density areas. Ultrasonography demonstrated hyperechoic, heterogeneous tumors. The tumors were shown to be hypovascular and adrenal in origin on the angiogram. An operation was performed because of complaint of flank pain in the first case and hypertension associated with elevated plasma renin activity in the second case. The pathological study disclosed typical adrenal myelolipoma with a mixture of hematopoietic and adipose tissue. Adrenal myelolipoma is clinically unusual and only 41 cases with premortem diagnosis have been reported in English literature. We herein report the 14th and 15th cases in Japan. As computerized tomography and ultrasonography become more widely used, we believe that the number of cases difficult to differentiate from a malignancy will increase.