Peyronie's disease — medically also known as Induratio Penis Plastica (IPP) — is a chronic condition of the penis. In the course of this disease, scar tissue ("plaque") forms at one or more locations along the penile shaft, progressively calcifying over time. Patients may perceive these plaques as small hardened nodules that can be felt even in the flaccid state. These hardened areas prevent the erectile tissue from expanding evenly during an erection, causing the erect penis to appear bent, curved, or otherwise deformed.