Peroni's disease, or fibrous spongitis, is a connective tissue disease involving the growth of fibrous plaque in penis.

Peroni's disease is a fibrotic lesion located between the corpus cavernosum and the tunica albuginea, and there are single or multiple pathological plaques on the corpus cavernosum. Francois de la peyronie (Peroni)1743 described the characteristics of fibrous spongiform inflammation of penis in his paper, so it was named peroni's disease. Peroni's disease is also called unnatural induration of penis, fibromatosis of penis and induration of penis. This disease is characterized by the damage of the white membrane of the corpus cavernosum. During erection, the penis bends to the injured side, which may be related to several minor injuries of the penis, but the specific reason is unknown. The lesion is located in the honeycomb connective tissue between the corpus cavernosum and the tunica albuginea. Microscopically, lymphocytes and plasma cells infiltrated around the blood vessels in the connective tissue layer in the early stage, and then plaques dominated by collagen fibers were formed near the diaphragm of the corpus cavernosum.