[Nevoid bundle hairs].

The document reported on two cases of naevoid bundle hair on the scalp, characterized by an abnormal grouping of hairs emerging from a single follicle ostium. Although the hairs originated from separate follicles, they fused into a common outer hair root sheath above the sebaceous gland. This sheath showed abnormal reactivity with monoclonal antibodies against keratin but normal reactivity with anti-filaggrin. Naevoid bundle hair was considered an atavistic hair growth pattern.