Neurofollicular hamartoma. A new histogenetic interpretation.

Neurofollicular hamartoma is a recently described entity characterized histopathologically by fascicles of spindle cells that are haphazardly arranged and laterally delimited by hyperplastic folliculo-sebaceous units. Immunohistochemical studies have shown the presence of a few S-100-positive cells scattered among the spindle cells. We report five cases of this peculiar entity and compare them to two examples of trichodiscomas. Both hamartomas were characterized by proliferations of spindle cells in close association with prominent folliculo-sebaceous units. Based on the clinical and histopathological findings, as well as the immunoperoxidase stains, we conclude that neurofollicular hamartomas are not different from trichodiscomas and fibrofolliculomas.