Follicular hybrid cyst (trichilemmal cyst and pilomatricoma) arising within a nevus sebaceus.

We report a case of follicular hybrid cyst arising in a nevus sebaceus. Histopathologic findings showed one part with the features of a trichilemmal cyst and the other part with those of a pilomatricoma. To our knowledge, this is the first case of follicular hybrid cyst associated with nevus sebaceus. We consider that the cyst in our case is derived from the hair matrix and from the follicular isthmus.