PAPILLOMA LINEARE.
The affection of the skin to which attention is now briefly called under the name of linear papilloma is somewhat rare and is described in the text books of dermatology under a variety of titles. It is frequently congenital, often develops in childhood, but may first appear in later life. It is characterized by warty excrescences, either colorless or pigmented, occurring in small groups running in one or more lines for some distance over the surface of the skin and frequently appearing upon only one side of the body. The neck, trunk, or one of the extremities may be the seat of the disease, and in rare cases the greater portion of the body may be affected. In congenital cases the warty outgrowth is apt to be fibrous and tough, while in cases developing later in life the lesions are softer, sometimes slightly scaly, and far more amenable to treatment. In some cases they have been known to disappear spontaneously or after some cutaneous exanthem, but a tendency to reappear upon the same site is usually manifested.
Of the names which have been applied to the affection the following may be mentioned: ichthyosis hystrix scu localis, ichthyosis linearis neuropathica, naevus verrucosus, naevus unius lateris, nerve naevus, and papilloma neuroticum.
The dark, fissured masses sometimes observed about the elbows and knees in severe cases of ichthyosis bear some resemblance to the warty lines seen in this affection, but they are simply accumulations of epidermis and not papillomatous in character. In linear papilloma, however extensive it may be, there is nothing suggestive of ordinary ichthyosis, and the statement made by some writers that a xerodermatous or parchment-like condition of the skin often coexists with papillomatous streaks is by no means in accord with my experience. The disease in question might be classed with ordinary verruca (warts) more justly than with ichthyosis.
