spinal dermal sinus
A rare closed dysraphism with stalk characterized by a dorsal midline dermal sinus tract lined by keratinizing stratified squamous epithelium extending to the the intrathecal space. Other components such as hair follicles and shafts, mesenchymal derivatives (blood vessels and fibrous tissue) and occasionally nerve fibers can be observed. Inflamed granulation tissue containing mixed neutrophils, plasma cells, lymphocytes, and histiocytes is consistently found in the tract. It can also be associated with an intradural dermoid cyst. This malformation is at risk to cause intrathecal infections (meningitis, empyema) that justify a prophylactic surgery.