The malignant wart, already mentioned, is a prickle-celled tumor. Papillary epithelial tumors may be malignant from the onset, or may develop malignancy from a benign growth, but, as a rule, metastases from these tumors do not take place. Bloodgood* describes such a growth springing from the mucocutaneous border of the lower lip in a feeble old man, the •tumor being of one year's duration. The tumor had a large papillary surface, which overhung normal skin, and was attached by a pedicle to the edge of the mucous membrane. There was no induration below the pedicle. Because of the above facts the operator was able to conclude on operation, that the tumor was either benign or a very early papillary epithelioma. Local excision was performed, and early cancerous changes, limited to the wart, were found. Further operation was deemed unnecessary, and there was no recurrence. Bloodgood has observed seventeen malignant warts, and all but one has remained cured by operation, and in that case the local incision was not sufficiently broad. In nine cases merely a wedge-shaped piece was removed, and in eight the cervical glands were dissected out. In not a single instance did the glands show metastases. The duration of the warts had been: in two eases, two months; in one case, five months; in the remaining cases more than six months, the longest ten years.

Fig. 81.-Prickle-celled cancer of the lower lip of eight months' duration, lesion developing upon an old existing fissure. Patient refused operation upon glands of the neck and died eighteen months later as the result of metastases. (Heid-ingsfeld's collection).