Dermal cylindroma

In dermatologic pathology, a dermal cylindroma, also dermal eccrine cylindroma or cutaneous cylindroma ) and (less specifically) cylindroma, is a benign adnexal tumor that occurs on the scalp and forehead.

Multiple cylindromas may grow together in a "hat-like" configuration, sometimes referred to as a turban tumor. Cylindromas are uncommon dysplasias of skin appendages.

Histology
Dermal cylindromas are:
 * Dermal lesions consisting of nests of cells that are surrounded by hyaline (i.e., glassy, eosinophilic, acellular) material and have:
 * Hyperchromatic nuclei that may palisade (columnar nuclei arranged around the periphery of the cell nests with their short axis tangential to the nest periphery), and
 * Cells with lighter staining ovoid nuclei at their centre.

They lack of a significant number of lymphocytes; this differentiates them from spiradenomas.