What causes penile curvature?
In Peyronie’s disease, a disorder of penile curvature, a scar or plaque develops under the skin within tissue called the tunica albuginea of the penis. This is not a plaque that develops outside or inside of the tunica albuginea, but is a change of a portion of the tunica albuginea itself.
This scar is not elastic like normal tissue and this inability of a portion of the penis to stretch during an erection is what causes penile curvature. Consider the example of a rubber balloon. When the balloon is filled with water, it becomes longer, wider, and more firm (picture below on the right). When a penis becomes erect, instead of water, blood fills the penis and instead of rubber, there is tunica albuginea. As blood fills the space inside the tunica albuginea, the penis gets longer, wider, and more firm. Now, imagine if it were possible to replace the rubber along one side of the balloon with inelastic plastic. Then, when filled the side that contains plastic will not expand as much as the all-rubber side.. This will lead to a curvature towards the side that contains the plastic.
In Peyronie’s disease, the penis generally curves in the direction of the plaque. For example, if the plaque is mostly along the top (dorsal) shaft of the penis (the most common location of plaque), the penis will curve upward during erection. In most but not all cases of Peyronie’s Disease, the plaque is along the top of the penis and therefore the curve of the penis is usually upward. Many of our patients are under the impression that the plaque can just be scraped off or simply removed. The problem is that the plaque is part of the tunica albuginea and removing the plaque will create a hole in the penis. Using the balloon example, the plastic is not attached to the balloon. The rubber in one area is replaced by plastic and removing the plastic would create a hole in the balloon, leading to the water leaking out. Nevertheless, the penile curvature can be corrected.
The cause of the scarring associated with the development of a bent penis is not known. It may result from injury to the penis, perhaps during sexual intercourse. This may represent a specific event or repeated minor trauma. A significant number of patients with Peyronie’s disease also have Dupuytren’s contracture, a fibrotic process involving the hand. In rare cases, there can also be contractures in the feet and this is called Lederhose disease. It is therefore thought that certain individuals are genetically predisposed to the condition.
Dupeytren’s Contracture associated with Peyronie’s Disease
Dupeytren’s Contracture, another view
A patient with bilateral Dupeytren’s and Peyronie’s Disease
Lederhose disease in a patient with Peyronie’s Disease