It characterizes the benign primary cutaneous apocrine neoplasm syringocystadenoma papilliferum, which also shows a papillary architecture and elicits a lymphoplasmacytic inflammatory response.
Syringocystadenocarcinoma papilliferum is a rare neoplasm of apocrine glands and is the malignant counterpart of the more common benign syringocystadenoma papilliferum.
Histologically, syringocystadenocarcinoma papilliferum resembles syringocystadenoma papilliferum and is marked by funnel-shaped epidermal invaginations demonstrating a gradual transition from keratinizing squamous epithelium at the surface to variable layers of glandular epithelium within subjacent cystic spaces.
The invasive carcinoma, together with an in situ element, also supports the idea that syringocystadenocarcinoma papilliferum arises out of a syringocystadenoma papilliferum.
The benign syringocystadenoma papilliferum has been reported to show carcinoembryonic antigen and epithelial membrane antigen expression at the apical portion of the luminal cells as well as CK7 positivity in the luminal cells, whereas the basal cells express other keratins, such as CK5/6 and CK14, with patchy smooth muscle actin staining.
A case of syringocystadenocarcinoma papilliferum in situ occurring partially in syringocystadenoma papilliferum.