IT IS THE thesis of this paper that the basal cell epitheliomas originate from incompletely differentiated embryonal cells rather than from dedifferentiated anaplastic cells. It is my belief that basal cell epitheliomas are not carcinomas, not derived from basal cells, but are nevoid tumors (hamartomas) derived from arrested embryonal primary epithelial germ cells. They represent the least differentiated group of primary epithelial germ tumors. In my classification of the primary epithelial germ tumors they are grouped as nonorganic hamartomas (table in part I).1 The name basal cell epithelioma has been retained in spite of my belief that basal cell epitheliomas do not originate from basal cells, because its use is so well established. The designation basal cell carcinoma should, however, be avoided.
The proposition that basal cell epitheliomas are not carcinomas is based on the fact that they probably never metastasize.
Niles2 stated that metastasis of a pure