The curvature of the penis may be congenital or acquired. In this second case it is almost always due to induratio penis plastica (IPP). On the shaft of the penis develops a collagen tissue plaque or scar tissue, which replaces the elastic fibers.
The scar tissue, known as plaque of Peyronie, can harden the penis or reduce the elasticity and can cause the curvature during erection, because the affected tissue by plaque is not extensible, so it determines the curvature.
The disease can manifest with a variable curvature (measured in degrees) and may involve several stages of severity, characterized by pain during erection, negative impact on sexual relations, on their frequency and, in general, on the quality of life of the patients. It is a disease with an initial inflammatory component: this preliminary phase has a low awareness and a variable course that tends to resolve spontaneously in less than 13% of cases. After about 12 months from the onset of the disease it is reached in a stable form, characterized by a more or less accentuated curvature during the phase of erection of the penis. Although the incidence of Peyronie’s disease is estimated to be between 3% and 9%, it is still an underdiagnosed disease and often undertreated.