(Cornu humanum; Cutaneous horn)
Definition :- A rare, circumscribed, horny excrescence of variable size and shape.
Symptoms. – These growths are usually single, although they may be multiple and are most frequently found on the scalp, face and male genitalia. They average about an inch in length, although they may measure as much as twelve inches. Usually of curved shape and of hard substance like the horns of the lower animals, their surface is tough, hard, dry, wrinkled transversely and striated longitudinally. In color they may be greenish-yellow, brown or black. Having grown to a certain size they are apt to drop off, leaving an eroded surface from which a new horn is likely to grow. It is from this eroded surface that epitheliomas may develop according to Lebert in about twelve per cent. of all cases.
Etiology and Pathology. – Although cutaneous horns have been noted in infancy, most cases occur after middle life. They originate from senile warts, ruptured sebaceous cysts, scars (especially those burns), and the distorted hypertrophy of toe nails is bed-ridden patients. These growths are composed of densely laminated cornified cells which are arranged in concentric columns.
Prognosis and Treatment. – Cutaneous horns are easily destroyed. Apart from possible cancerous degeneration, they have no effects upon the general health. However, they should be removed in a thorough manner. This may be done by softening with hot alkaline solutions and cutting or paring them down to the base which should be thoroughly excised or destroyed by high-frequency sparking, mild fulguration or solidified carbon di oxide.