Case Number : CT0122 Adam_Bates

Syringocystadenoma papilliferum (papillary syringadenoma) with some suggestion it is arising in a naevus sebaceous in fig 1.
 

Syringocystadenoma papilliferum.
 

Syringocystadenoma papilliferum, I agree with the component of naevus sebaceous. I would like to know if figures 3 and 4 are hidding something interesting.
 

Collisional tumour of syringocystadenoma and trichilemmoma (which tries to form cutaneous horn) in the context of sebaceous naevus
 

Cystic lumen and projecting papillary fronds, both lined by two-layered epithelium with luminal cells exhibiting decapitation snouts. Stroma with inflammatory infiltrate rich in plasma cells.
There is associated acanthotic epidermis surrounding hyperkeratotic column.
I would call this syringocystadenoma papilliferum associated with apocrine acrosyringeal keratosis.

Syringocystadenoma and trichilemmoma in nevus sebaceous

This is syringocystadenoma papilliferum and early trichilemmoma.