Blood microcirculation in the lymph node in xanthomatosis.

Twenty-five New Zealand white rabbits were placed on an atherogenic diet for 7 to 160 days to induce xanthomatosis. The microvascular morphology of the popliteal lymph node was studied throughout the development of xanthomatous replacement. The lymph nodes were serially sectioned and studied histologically and by microangiography. In animals which were on the atherogenic diet for over 90 days, foam cells replaced almost all of the lymphoid elements. Xanthomata appeared first as islands in the subcortical area and later spread to the medullary cords and the cortex. The xanthomata were highly vascular and contained a rich and dense capillary network of 5 to 7 mu vessels which were incorporated in the normal blood supply of the lymph node. The richness of capillary supply exceeds the hypervascularity observed during the immune response. The morphology of the capillaries raises the possibility of angiogenesis.