NCIt definition : A benign neoplasm arising from the outer hair sheath and infundibulum. It occurs in
the head and neck, usually on the face. It usually presents as an exophytic wart-like
lesion or a dome-shaped lesion with a smooth surface. Morphologically, it is characterized
by the proliferation of cuboidal cells with clear or eosinophilic cytoplasm in the
dermis with connection to the epidermis/hair follicle. There is peripheral cellular
palisading, and the lesion is surrounded by a hyaline band.;
Alternative definition : CDISC: A benign hair follicle neoplasm in the outer hair sheath and infundibulum,
characterized by central cells showing highly eosinophilic amorphous keratin.;