Histologic features of cylindroma

(A) Cylindromas contain many small islands of basaloid keratinocytes closely opposed to one another in a pattern resembling the pieces of a jigsaw puzzle (H&E 40x).
(B) Prominent pink, hyalinized basement membrane substance surrounds the individual tumor aggregations and is present in drop-like fashion between the keratinocytes. Ductal differentiation is present (H&E 200x).