Host-tumor relationships in basal cell and squamous cell cancer of the skin.

We suggest that aggressive clinical tumor behavior correlates with the presence of squamous differentiation and with irregularities in the peripheral palisading of basal cell carcinomas. The concept of non-melanoma skin cancer being a basosquamous continuum may help in formulating a method for prognosis in patients who had removed tumors with a pathologist's report of a "positive margin."