Etiology of Peyronie’s Disease
Studies that suggest abnormal wound healing in men with PD lend support to the model of trauma as a necessary step in the pathophysiology of PD. Enzymes in the matrix metalloprotein family have important antifibrotic properties, while TGF-b has been shown in cell culture and animal models to be an important profibrotic mediator of plaque formation. These factors in addition to the effect of plasminogen activator inhibitor type 1 and osteoblast-stimulating factor 1 may help explain the balance between pro- and antifibrotic enzymatic processes that likely contributes significantly to the development of penile lesions and subsequent penile abnormalities.
Abnormal wound healing resulting from underlying genetic abnormalities may contribute to some cases of Peyronie’s disease. The presence of Dupuytren’s contractures among some men with Peyronie’s disease suggests that a genetic predisposition to scarring and fibrosis may be associated with tunica albuginea fibrosis and scarring. Another example is the Kelami syndrome, also known as urethral manipulation syndrome, described as ventral penile curvature occurring after urethral manipulation. Sonographic evidence suggests that the underlying mechanism for penile curvature in this setting is one of periurethral scarring, perhaps secondary to inflammation from urethral manipulation. It has also been demonstrated that among men with Paget’s disease, a chronic skeletal condition leading to painful bony deformities, 32% had penile lesions consistent with PD.
Loss of flexibility of the tunica albuginea results in differential expansion of the tunica during erection with subsequent penile curvature or deformity. The degree of curvature and volume of plaque is highly variable upon presentation. Curvature can range from nearly straight (15°) to 180° in the most severe cases. Plaques can be single or multiple and are associ-ated with a variety of penile deformities. While the most common direction of curvature is dorsal, ventral, lateral, and complex curvatures are frequently seen. Noncurvature deformities range from “notching” to circumferential “hourglass” defects. Penile shortening is a commonly reported symptom and causes great concern to patients.
Although some men with PD have erectile dysfunction, this may be related to age or chronic disease rather than representing a causal relationship. Multiple reports have described a prevalence of erectile dysfunction as high as 80–100% among men with PD; however, a recent study suggests that only one-third of men with PD also have erectile dysfunction. Further, given that PD is associated with diabetes and erectile dysfunction among older men with PD, chronic medical conditions may explain the observed relationship between PD and erectile dysfunction.
There are several publications that highlight the emotional and psychosocial impact of PD. Patients often have a variety of psychosexual complaints, including poor self-image, emotional, and relationship difficulties. It has also been shown that almost half of men with PD had clinically significant depression. A challenge for clinicians and researchers is the lack of a validated quality of life measure for men with PD; however, these measures are being developed.