Their growth is usually slow, and, after having attained a certain size, they not infrequently become loose and fall off; they are almost always reproduced.
#What is the cause of these horny growths?#
The cause is not known; appearing about the genitalia, they usually develop from acuminated warts. They are rare formations.
Horns consist of closely agglutinated epidermic cells, forming small columns or rods; in the columns themselves the cells are arranged concentrically. In the base are found hypertrophic papillæ and some bloodvessels. They have their starting-point in the rete mucosum, either from that lying above the papillæ or that lining the follicles and glands.
#Does epitheliomatous degeneration of the base ever occur?#
Cutaneous horns may be readily and permanently removed.
Treatment consists in detachment, and subsequent destruction of the base; the former is accomplished by dissecting the horn away from the base or forcibly breaking it off, the latter by means of any of the well-known caustics, such as caustic potash, chloride of zinc and the galvano-cautery.
Another method is to excise the base, the horn coming away with it; this necessitates, however, considerable loss of tissue.
Verruca, or wart, is a hard or soft, rounded, flat, acuminated or filiform, circumscribed epidermal and papillary growth.
#Name the several varieties of warts met with.#
Verruca vulgaris, verruca plana, verruca plana juvenilis, verruca digitata, verruca filifortnis and verruca acuminata.
This is the common wart, occurring mostly upon the hands. It is rounded, elevated, circumscribed, hard and horny, with a broad base, and usually the size of a pea. At first it is smooth and covered with slightly thickened epidermis, but later this disappears to some extent, the hypertrophied papillæ, appearing as minute elevations, making up the growth. One, several or more may be present.
This is the so-called flat wart, and occurs commonly upon the back, especially in elderly people (_verruca senilis_, _keratosis pigmentosa_). It is, as a rule, but slightly elevated, is usually dark in color, and of the size of a pea or finger-nail.
The warts are mostly pin-head in size, flat, but slightly elevated, rounded, irregular or square-shaped, and of a light yellowish-brown color. They bear resemblance to lichen planus papules. They are apt to be numerous, often becoming aggregated or fused, and occur usually in young children, and, as a rule, on the face and hands.