Fibrous cap explained

The fibrous cap is a layer of fibrous connective tissue, which is thicker and less cellular than the normal intima, found in atheromatous plaques. The fibrous cap contains macrophages and smooth muscle cells.^[1] The fibrous cap of an atheroma is composed of bundles of muscle cells, macrophages, foam cells, lymphocytes, collagen and elastin.^[1] An atheroma with a cap is termed a fibrous cap atheroma.

Rupture

The rupture of a fibrous cap can lead to a stroke, or a heart attack either of which has the potential to be fatal.^[2] The fibrous cap is prone to rupture and ulceration which can lead to thrombosis. In advanced lesions, further complications may arise including calcification of the fibrous cap.^[3]

References

1. Hansson. Göran K.. Libby, Peter. The immune response in atherosclerosis: a double-edged sword. Nature Reviews Immunology. July 2006. 6. 7. 508–519. 10.1038/nri1882. 16778830.
2. Web site: Wissing . T. B. . Van der Heiden . K. . Serra . S. M. . Smits . A. I. P. M. . Bouten . C. V. C. . Gijsen . F. J. H. . Tissue-engineered collagenous fibrous cap models to systematically elucidate atherosclerotic plaque rupture . Scientific Reports . 27 March 2025 . 5434 . en . 10.1038/s41598-022-08425-4 . 31 March 2022.
3. Swirski. F. K.. Nahrendorf, M.. Leukocyte Behavior in Atherosclerosis, Myocardial Infarction, and Heart Failure. Science. 10 January 2013. 339. 6116. 161–166. 10.1126/science.1230719. 23307733. 3891792. 2013Sci...339..161S .