The clot stays in the lung arteries and becomes a fibrous tissue.

The lungs fill up with fibrous tissue, which traps fluid in them.

Second, she discovered that, inside, the cyst was composed almost entirely of tough, fibrous tissue.

These are hard deposits of cholesterol and fibrous tissue that build up on blood vessel walls.

A mutation of the body's repair mechanism causes fibrous tissue (including muscle, tendon, and ligament) to be ossified spontaneously or when damaged.