Eczema, lichen planus and psoriasis (Hartzell*, Bloodgood*) occasionally give rise to cancer of the skin, but in the vast majority of the cases reported it is probable that either arsenic or x-ray was the true cause.
That the lesions of blastomycosis may become cancerous has been shown by Bloodgood* in a case that the writer was fortunate enough to see with him.
Bloodgood frequently refers to sinuses and fistulas as being the starting points of epithelial neoplasms, but admits that, when one considers the frequency of such conditions, the subsequent development of cancer is rare. He also mentions one case of malignant change in a bedsore.
Wens may serve as the starting points of cancer according to Bloodgood,* who has recorded three cases where malignant change took place in the wall.
Vascular or pigmented nevi not infrequently become the starting points of sarcomata, and rarely of carcinomata of the skin.
The fibro-epitheliomata of the skin, commonly called papillomas, frequently give rise to either basal- or prickle-celled cancers, especially when they are subject to chronic irritation.
*Hartzell: Amer. Jour. Med. Scien., 1899.
*Bloodgood: Progressive Medicine, Dec, 1907.
*Bloodgood: Progressive Medicine, Dec, 1913.
In a recent review of the literature Sutton* points out that the line separating malignant from benign epithelial growths of the skin is often a very obscure one, and that tumors of the rodent ulcer type may originate in the lesions of the so-called multiple benign cystic epitheliomata. He does not, however, agree with Heidingsfeld,* who believes that all growths of this type are premalignant in character.
Both Montgomery* and Sutton* have shown how frequently cancer of the lip starts in seborrheic patches, and for years it has been known that cancer of the tongue frequently originates in syphilitic lesions as well as in leukoplakia.
Bloodgood* states that every case of cancer of the skin of which he has a complete record originated from some abnormality of the skin, and not from normal epidermis. He also states that out of forty cases of cutaneous sarcoma, thirty-two originated from distinct skin lesions, usually the scars of burns. These statements show that, if all apparently harmless cutaneous growths were removed, we should have fewer cancers. It also means that we should do our best to promptly heal all lesions, and not allow them to drag along.
*Sutton: Amer. Jour. Med. Scien., 1913, cxlv, 819. M Heidingsfeld: Jour. Amer. Med. Assn., 1912, lvix, 256. 38 Montgomery: Jour. Cutan. Dis., 1913, xxx, 82. 84 Sutton: Jour. Amer. Med. Assn., 1913, lx, 1774. "Bloodgood: Progressive Medicine, Dec, 1912.