====== Spinal dermal sinus ======


===== General information =====

May appear as a [[dimple]] or as a [[sinus]], with or without hairs, usually very close to [[midline]], with an opening of only 1–2mm. Surrounding skin may be normal, pigmented (“port wine” discoloration), or distorted by an underlying mass.

The sinus may terminate superficially, may connect with the [[coccyx]], or may traverse between normal vertebrae or through bifid spines to the dural tube. It may widen at any point along its path to form a cyst; called an [[epidermoid cyst]] if lined with stratified squamous epithelium and containing only keratin from desquamated epithelium, or called a [[dermoid cyst]] if also lined with dermis (containing skin appendages, such as hair follicles and sebaceous glands) and also containing sebum and hair.

Although innocuous in appearance, they are a potential pathway for intradural infection which may result in meningitis (sometimes recurrent) and/or intrathecal abscess. Less serious, a local infection may occur. The lining dermis contains normal skin appendages which may result in hair, sebum, desquamated epithelium and cholesterol, within the tract. As a result, the contents of the sinus tract are irritating and can cause a sterile (chemical) meningitis with possible delayed [[arachnoiditis]] if it
enters the dural space.

Incidence of a presumed [[sacral sinus]] (a dimple whose bottom could not be seen on skin retraction):
1.2% of neonates