Pathology.—It is not definitely known whether the disease is epitheliomatous from the start, or whether it begins as an eczematous dermatitis and becomes ma lignant in consequence of the epithelio matous degeneration of the skin. The glandular structures of the nipple are especially liable to malignant degenera tion, and it is probable that any long continued irritation of the epithelial ele ments would be followed, in persons with a predisposition to epithelial overgrowth, by malignant disease. Upon this as sumption, the view that the primary dis ease is an eczema or a dermatitis, and that malignancy is secondary, is a ra tional one.
Microscopical studies of the disease by Thin and Wile have shown the epithelial infiltration present at a very early stage. It may be said, however, that when the diagnosis of malignant dermatitis or Paget's disease can be made, the trouble is no longer an eczema, whatever it may have been at an earlier period.
Case of malignant papillary derma titis occurring on the breast of a woman of 45. The morbid changes are inflam mation of the papillary layer, with cedema and vacuolation of the epidermic cells, the latter being followed by complete destruction or by abnormal proliferation in different situations. Sec ondary to these changes there is pro liferation of the lining of the galactif erous ducts and glands. The prolifer ated cells finally break through the basement-membrane into the surround ing tissue, at which point malignant in fection begins. F. H. Wiggin and J. A. Fordyce (N. Y. Med. Jour., Oct. 2, '97).
Diagnosis. — Diagnostic features of naalignant dermatitis as differentiated from eczema of the nipple are:— 1. Its occurrence in women over 40 years of age, while eczema of the nipple is more frequent in the child-bearing age, and especially during lactation.
2. The affected surface is red, raw, and granular-looking.
3. There is decided superficial, well defined induration in place of the dif fuse, leathery infiltration of eczema.
Finally, while eczema is often ob stinate, it usually yields to proper local treatment; while malignant dermatitis is not curable by any means short of cauterization or removal with the knife.
Treatment. —In reference to the treat ment of malignant dermatitis, Sir James Paget said in his paper above referred to: "In practice the question must be some times raised whether a part, through whose disease or degeneracy cancer is very likely to be induced, should not be removed. In the member of a family in
which cancer has frequently occurred, and who is at or beyond middle age, the risk is certainly very great that such an eruption on the arcola, as I have de scribed, will be followed within a year or two by cancer of the breast. Should not, then, the whole diseased portion of the skin be destroyed or removed as soon as it appears incurable by milder means?" The answer to the question is self-evi dent, in view of the history of the dis ease. If a diagnosis of malignant derma titis is positively made, there can be no other rational treatment than such as would be appropriate for epithelioma; namely: destruction of the diseased skin by cautery or caustics, or removal of the entire breast. In cases of doubt, the ap proved remedies for eczema may be tried, but too much time should not be wasted in temporizing expedients.
Pyrogallic-acid ointment, 3 drachms to the ounce; lactic acid; chloride-of zinc paste, of varying strength; chromic acid and arsenical pastes, the best of which is Marsden's M acidi arsenosi, pulv. g. acacim, of each, p. e.; mix and make a stiff paste with water just before using), may all be used with good effect. Chromic acid in concentrated solution is the least—Marsden's paste the most— painful of these applications. The ar senical paste should not be applied over a surface of more than one square inch at a time, as otherwise sufficient arsenic may be absorbed to cause symptoms of poisoning. The pain of the application is very severe, and as the caustic must remain upon the part at least twenty-four hours, the suffering is always consider able. When the paste is applied a piece of lint is pressed upon it which absorbs the surplus and prevents its spreading. After twenty-four hours, a poultice is applied, which soon causes a separation of the slough. The resulting ulcer is usually healthy in appearance and heals readily under simple applications, if all the degenerated tissue has been de stroyed.
The galvanocautery and thermocau tery are trustworthy methods for destroy ing the morbid tissue.
When the area involved is large, the best treatment is thorough extirpation of the entire breast.