👉 Propterygium is a type of benign skin growth that occurs on the outer layer of the penis. It is usually small, round, and smooth, but can also be irregular in shape or size depending on its location. Propterygium can occur in any part of the penis, including the shaft, head, or glans (the base of the penis). It is often associated with a lower risk of certain sexual health conditions such as Peyronie's disease.