The distribution of lipids in malignant hypertensive fibrinoid necrosis

The fibrinoid necrosis developing in the course of experimental malignant hypertension was examined for the presence, localization and appearance of lipids. In the initial stage of hypertension, only sudanophilic droplets were demonstrable in the necrotic muscle cells of the media, but later diffuse sudanophilia was apparent over nearly the entire cell body. The subendothelial fibrinoid developing during the second stage was Sudan negative, whereas the necrotic medial cells exhibited a distinct sudanophilia. At the same time a considerable extra- and intracellular sudanophilia also appeared in the perivascular granulation tissue, but it tended to decrease or entirely disappear during the third stage. At this time, foam cells appeared in the subendothelial fibrinoid. Based on our findings, the sudanophilia of the media has been attributed to lipids rendered visible by phanerosis.