—Paget’s disease includes lesions now regarded as a precancerous stage, which appear upon the breasts and around the nipples of women during the middle decades of life. Something similar is seen in other parts of the body and in both sexes, but it is most common around the nipple on one side. For a long time it appears as an ordinary eczema, which, however, does not tend to heal but to spread, while the skin beneath becomes more or less infiltrated. A gradual retrocession of the nipple is usually seen. Certain discomfort accompanies the lesion, which may go on indefinitely until it becomes unmistakably cancerous. This is a precursor not so much of round-cell cancer (scirrhus) as of epithelioma. Eczema of the nipple is to be regarded with suspicion, especially when occurring after the menopause. Until diagnosis is fairly established it is best treated with soothing applications. So soon as the cancerous stage has been determined the breast should be removed. (See [Plate XXVI].)
Other forms of malignant or border-land tumors which occur upon the skin are chimney-sweeper’s cancer, paraffin cancer, and that met with in aniline workers. Chimney-sweeper’s cancer was the name applied to epithelioma of the scrotum occurring among a class of laborers whose occupation is now almost entirely extinct. It began usually as papilloma and merged into epithelioma. Among workers in paraffin and coal-tar factories there is an analogous lesion, the result of surface irritation, the skin becoming dry, thickened, covered with acne-like pustules, and then with papillomas which ulcerate and frequently change over into true epitheliomas.
Sarcoma.
—Only the outer layers of the skin are truly epiblastic. In the depths of the integument mesoblastic elements enter largely, and from these various forms of sarcoma may develop. These have already been treated in the chapter on Tumors. They may be single or multiple, and a general disseminated sarcomatosis is occasionally observed. It corresponds to miliary tuberculosis, but presents many distinctive lesions in the skin, by which it may be easily recognized. A form of multiple pigmented sarcoma involving the hands is represented in [Fig. 109]. These growths are almost always tender on pressure and more or less painful. They coalesce and finally form fatal lesions.
Melanoma.
—This term was introduced by Virchow, who made it cover all pigmented growths. By common consent it is today limited to tumors of the skin and uveal tract which contain pigment; metastases may occur in any or all of them. They occur as malignant degenerations of nevi, moles, and other small growths. Pathologists are still disputing as to whether they should be considered sarcomas or endotheliomas. The coloring matter which they contain is amorphous, finely granular material, lying between the cells in moles, but occurring free in the tissues and blood and even in the urine. It is soluble in strong alkalies, from which it can be recovered as melanic acid, containing a small proportion of sulphur. Of its origin nothing is positively known. It seems to be generally accepted that the deposit of pigment is not of itself a causative agent of the growth of the tumor, but that the growth of cells and their pigmentation are coincident processes. Johnston has offered much evidence lately to the effect that growths from nevi are really of endothelial origin. Hutchinson has described melanotic whitlow. (See below, the [Nails].)
Melanoma is a pigmented ulcerating neoplasm, which possesses at first only a local malignancy like that of rodent ulcer; the more it assumes the endotheliomatous type of growth the more it tends to disseminate and to prove fatal.
The melanoma arising from a mole or nevus, thus known as melano-endothelioma, begins to increase in size and becomes more full, as well as to assume a darker tint. For a variable time it is a single, rather firm, gradually growing, flat tumor, rarely ulcerating, but sometimes exuding a thin dark fluid. Suddenly there appears rapid local spread as well as dissemination. The latter may be first noted in the adjoining lymph nodes. Thus numerous secondary tumors may be felt in and beneath the skin, at first colorless, becoming more or less rapidly pigmented. Metastasis may take place to every organ in the body, but usually the liver and lungs—less often the brain—are involved. In one case known to the writer the heart was a mass of nodules of this same secondary character.
Another expression of the same serious condition is seen in a lesion called by the French malignant lentigo, which also begins with pigmented spots, on the feet of old men, sometimes upon the face. These lesions cause thickening of the skin and early ulceration.
Rodent ulcer, which is one form of epithelioma, occasionally assumes the melanotic type, and is called melano-epithelioma.