Keratinizing squamous epithelium associated with Syringocystadenoma papilliferum differentiates towards infrainfundibulum: case report with immunohistochemical study of cytokeratins.

We describe a case of Syringocystadenoma papilliferum (SCAP) with keratinizing squamous epithelium in a 26-year-old female presenting with a dark brown to black nodule on her forehead. After surgical excision, the specimen was examined immunohistochemically using antibodies against cytokeratin (CK) 1, 8, 10, 14, 17, 18 and 19. Within the keratinizing squamous epithelium, CK1, 10, 14 and 17 were present, whereas the other CKs were absent. Based on CK expression, keratinizing squamous epithelium in SCAP seems to differentiate towards the infrainfundibulum.