What Is Peyronie’s Disease?
A slight natural curve to the erect penis is usually normal. But curvature that causes pain and difficulty with intercourse is a problem. The development of painful curvature is called Peyronie’s disease. Peyronie’s disease is due to a plaque (scar) that forms inside the penis.

Your Penile Anatomy
The shaft (body) of the penis consists of the corpora cavernosa, two columns of spongy tissue. During an erection, this tissue fills with blood, swells, and becomes rigid, creating an erection. A dense sheath of elastic tissue called the tunica surrounds the corpora. This tissue stretches as the penis becomes erect.

Painful Curvature
Peyronie’s disease occurs when a plaque (scar) develops on the fibrous sheath of tissue surrounding the corpora. The scar can form on any part of the penis, but often is found on the top or bottom. The scarred area of the tunica loses its elasticity, and so doesn’t stretch when the corpora swell. Because the tunica doesn’t stretch in that area, the erect penis curves in the direction of the scar.
Possible Causes
No one is sure just what causes the plaque. It may be the result of an injury to the erect penis or a blow to the groin. The plaque may also occur because of a problem with your immune system, which normally helps your body fight disease. Or the plaque may form for other, still unknown, reasons. It is certain, however, that Peyronie’s disease is not caused by sexually transmitted diseases and is not cancer.
Symptoms of Peyronie’s Disease
A hard area is usually felt below the skin of the penis in the area of the plaque.