SYRINGOCYSTADENOMA papilliferum with nevus sebaceus combined in one lesion as a mixed tumor is interesting, not alone for its comparative rarity, but because its occurrence in the past has been the basis for the belief that these two histologically distinct structures are thereby histogenetically related and that their presence is the end-result of a dysontogenesis.
Regarding the essential cellular make-up of syringocystadenoma papilliferum, opinion is far from unanimous. Almost all the reports of this relatively rare tumor have described it as of sweat-gland origin, with the definite inference that the sweat glands involved were of the eccrine type. This was based on the supposed presence of eccrine-type glands both in the matrix of the lesion itself and in the immediately adjacent areas. Thus, Arzt and Kumer,1 in the first description of combined syringocystadenoma papilliferum and nevus sebaceus (1925), referred to the glands as greatly dilated sweat glands, with