The papilla is the wart-shaped elevation in skin or mucous skin (such as the papilla vateri or papilla vallata).
A carcinoma is a neoplasie derived from epithelial tissue:
Morphological criteria allow further discrimination into:
These forms are similar to the original tissue or might grow glandular-like. Additionally there are tumors without any differention. They are called anaplastic or undifferentiated.
Epithelia can derive from all blastodermic layers. Therefore they cannot be sorted to a certain layer.