Atheromatosis and double media: uncommon vascular lesions of renal allografts

Study of 45 renal allograft nephrectomy specimens revealed the presence of relatively uncommon arterial vascular lesions: atheromatosis (12 cases) and a double layer of smooth muscle in the intima (Double Media) (4 cases). Histopathologic features of atheromatosis showed the presence of large lipid-laden cells localized in the intimal layer of arteries. Diagnosis of acute vascular rejection (AVR) was made in 19 cases. Diagnosis of chronic vascular rejection (CVR) was found in 4 cases. 22 cases showed lesions of both AVR and CVR. In 12 cases there was infiltration of the intima and media wall by foam cells closely resembling an atheromatous lesion. Four cases of Double Media were found in allografts with survival varying from 51 to 344 days. The presence of either atheromatous or double media does not correlate statistically with immunosuppressive treatment, blood pressure or with the presence of hypertriglyceridemia and/or hypercholesterolemia. Immunohistochemical investigation of atheromatosis revealed total negativity of the foam cells with antisera to: actin, myosin, desmin and myoglobin. Variable reactivity was observed with antisera to vimentin. Myointimal cells of Double Media expressed slight positivity for actin and vimentin. The double media lesion seems to be the result of a reparative vascular process secondary to rejection changes. Atheromatosis seems to be closely correlated to episodes of acute rejection. Vascular lesions in grafts are harbinger of poor prognosis. Double media lesion and atheromatosis do not seem to have a more unfavourable prognostic significance on the evolution of the transplants.