Cornu Cutaneum.
Cornu cutaneum (syn., cornu humanum, horny tumor) is characterized by the development of a true horny formation of variable size and shape, arising from the skin. The growth bears a striking similarity to the horns of the lower animals. It is a solid, dry, harsh, somewhat brittle formation, usually more or less tapering, conical, or rounded, crooked or twisted, with a laminated, irregular, and fissured surface, and of a grayish-yellow or brownish color. Horns vary as to size and form, being a few lines or several inches in length, with a broad base, and tapering toward the end. They may be broad and flat or elongate. They have a flattened or concave base resting directly upon the skin, with the underlying and surrounding tissue normal, slightly elevated, or inflamed and undergoing epithelial degeneration. In some cases the papillæ are much enlarged and extend up into the growth. Ordinarily, there is present but one growth, but in some instances several or a dozen or more have been observed in a single case. The face and scalp are favorite regions, and to a less degree the male genitalia. As a rule, the horns are painless, but if injured more or less pain is usually experienced about the base. They rarely develop before middle age, attain a certain size, and then tend to loosen and fall off, disclosing an ulcerating base, from which a new growth is usually reproduced. Epitheliomatous degeneration is not an uncommon sequela.
Anatomically, the growth has its origin in the deeper layers of the stratum mucosum, either from that lying directly over the papillæ or from that lining the follicles and glands. It is essentially an epidermic hypertrophy, similar or closely related to warty formation. A variable degree of papillary hypertrophy, the papillæ running up into the base of the horn, is invariably present, and precedes, doubtless, the horny outgrowth. The horny cells are massed together to form columns, and in the columns themselves are concentrically arranged. Blood-vessels also appear in the base of the growth. There can be no difficulty in the diagnosis. In regard to prognosis the possibility of degeneration into epithelioma is to be kept in view. If the horn becomes detached or is knocked off, it is almost invariably reproduced. Properly managed, horns are easily removed and permanent freedom assured. The possibility of epitheliomatous degeneration, as well as their unsightliness, demands active treatment. The formation is to be detached and the base thoroughly scraped with the dermal curette, and pyrogallic acid or arsenious acid applied, as in epithelial cancer; or it may be cauterized with zinc chloride or caustic potash. The galvano-cautery is also efficient, while in some cases excision may prove the best method of treatment. If the base is properly treated, a return of the growth rarely occurs.
Verruca.
Verruca, or wart, is a hard or soft, rounded, flat, or acuminated, circumscribed epidermal and papillary formation. There are several forms of warts. The most common variety, verruca vulgaris, is seen mostly upon the hands. It is usually split-pea-sized, elevated, circumscribed, rounded, with a broad base. At first there may be epidermal hypertrophy, but later this in a measure disappears, and the hypertrophic papillæ constitute the growth and are seen as minute elevations. It is firm, hard, or horny, and the color is ordinarily the same as the surrounding skin, but at times it is darker. The papillæ forming a wart are sometimes so irregularly developed as to make it appear lobulated, causing a cauliflower-like form. One, several, or great numbers may be present. Another form is verruca plana, or flat wart, differing from the ordinary wart described above in being flat and broad. It is usually the size of a split pea or finger-nail; occurs most frequently upon the back, especially in elderly people; and is usually brownish or blackish in color, constituting verruca senilis and keratosis pigmentosa. Verruca filiformis, a third variety, is a thread-like formation, usually about an eighth of an inch in length, occurring singly or in groups, and generally about the face, eyelids, and neck. Verruca digitata, another form, is mostly observed upon the scalp, and occurs as a slightly elevated formation, varying in size from a pea to a finger-nail, and marked by digitations, especially noticeable about the border.
Verruca acuminata (syn., venereal wart, pointed wart, moist wart, fig wart, pointed condyloma, cauliflower excrescence; verruca elevata) consists of one or more groups of acuminated or irregularly-shaped elevations, usually so closely packed together as to form a more or less solid mass of vegetations. At times they present an appearance of granulation tissue. In color they are usually pinkish or reddish, and are seen mainly about the genitalia, more particularly about the glans penis, on the inner side of the prepuce, and about the labia, and more rarely about the arms, axillæ, umbilicus, and toes. They are dry or moist according to the regions about which they occur and to other circumstances. The secretion from the moist formation is yellowish and of a puriform character, undergoing rapid decomposition and giving rise to a penetrating and often disgusting odor. They are seen both in men and women, especially in young people; develop rapidly, at times attaining the size of a fist; and variously resemble the cauliflower, cock's-comb, fungi, or raspberries.
The etiology of warts is not known. They are common to both sexes, and are much more frequent in the young. The various causes which, in the popular mind, are capable of producing these growths are merely conjectural, and in most instances have no foundation in fact. The acuminated wart is usually caused by irritating secretions. Anatomically, a wart consists of a connective-tissue growth as a basis, with papillary and slight epidermic hypertrophy, the interior of the growth containing vascular loops. In the acuminated or venereal wart there is considerable connective-tissue growth, the papillæ being markedly enlarged, the cells of the mucous layer highly developed, and the vascular supply abundant.
There is rarely any difficulty in the diagnosis, as the formations are well known and their characters pronounced. Prognosis is favorable; as a rule, the growths respond rapidly to treatment; at times, however, they prove obstinate. When they exist in numbers it is best to remove a part only of the whole manifestation at a time. Occasionally removal of several will be followed by spontaneous disappearance of the others. In some cases, indeed, after existing a shorter or longer period, they tend to disappear without treatment.
Excision by means of the curved scissors or a knife in some cases will be found the best method of dealing with them, their bases immediately after the operation being touched with nitrate of silver. Caustics, such as potassa, chromic acid, nitric acid, and acetic acid, may be employed, but strong remedies should be applied with care. Touching the growths frequently with a 10 to 20 per cent. solution of salicylic acid or a salicylic-acid plaster of the same strength, constantly applied, will be found useful. Multiple flat warts may be treated with a paste of precipitated sulphur and equal parts of acetic acid and glycerin, prepared at the time of using. In obstinate and relapsing cases the internal use of arsenic has been recommended. Stimulating powders and lotions, such as calomel, burnt alum, powdered savine, solution of chlorinated soda, and carbolic acid, may be used in the acuminated variety.
Nævus Pigmentosus.