Syringocystadenoma papilliferum

Syringocystadenoma papilliferum is a superficial adnexal tumor. Cuboidal and columnar keratinocytes form interconnecting ducts that interrupt the normal epidermis and extend into the dermis. Papillary projections into duct lumens and decapitation secretion are typical. An inflammatory infiltrate rich in plasma cells surrounds the proliferation. Syringocystadenoma papilliferum often arise within a nevus sebaceus, as is the case in this example (H&E 40x).