Fibrous cap

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.

Fibrous cap in an atheromatous plaque

Rupture

Histopathological progresssion

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]