Peyronie's Disease
In certain conditions a layer of benign fibrous tissue develops under the skin of the genitals. When erection occurs, this layer of tissue cannot stretch as well as the normal penile tissue, thus causing the genitals to curve. This can can make erection painful and sexual intercourse difficult. This is known as Peyronie's disease. The side and degree to which the genitals curves on erection would depend on the area and extent of the fibrous tissue formation. If the scar tissue forms on the upper side of the genitals, on erection the genitals will curve upwards. Similarly, if the fibrous tissue is on the lower side, the curvature will be downward. If there is fibrous tissue formation on both sides, the genital will appear irregular or indented on erection.