Chronic glomerular microangiopathy complicating metastatic carcinoma

Six cases of metastatic carcinoma associated with chronic glomerular microangiopathy and renal failure are reported. All had prominent subendothelial lucent zones and double-contoured glomerular basement membranes. There was no immunohistologic or ultrastructural evidence for immune complex entrapment in glomeruli. By immunohistology, material antigenically related to fibrin or fibrinogen was identified in glomerular basement membranes despite a paucity of typical fibrillar fibrin. Four patients received mitomycin C before the onset of renal disease, and one patient received chemotherapy other than mitomycin C before development of renal failure. One patient had no chemotherapy but was given radiotherapy, which did not include the kidneys in the irradiated field. These six cases emphasize the diverse pathophysiologic mechanisms by which glomerular microangiopathy may arise in metastatic carcinoma.