Horny growth of the penis
Horny growths on the skin, also known as cornu cutaneum, are keratinous skin tumors, caused by overgrowth of keratin in the dermis. Since they’re avascular (they have no bloodflow), they can be easily removed with a scalpel or sharp razor, but the underlying condition will almost always reappear if the site is not treated with radiation, chemotherapy, or (occasionally) cryotherapy.
Diseases and Surgery of the Genito-Urinary System. Francis Watson, 1908.