Midline cutaneous and spinal defects. Midline cutaneous abnormalities associated with occult spinal disorders.

Failure of separation of the neuroectoderm from the epithellal ectoderm to proceed in an orderly and complete fashion results in a wide variety of defects involving the skin, spinal cord, and cauda equina, as well as the surrounding structures of mesodermal origin. Congenital dermal sinuses occur most commonly in the lumbosacral region, are usually associated with a spina bifida, and may connect the skin directly to the spinal canal. Epidermoid or dermoid cysts may form at any point along a dermal sinus. Four types of cutaneous or subcutaneous abnormalities commonly seen associated with occult spinal disorders are abnormal hair, angioma, lipoma, and dimple. It is essential that these lesions are investigated at an early age, since surgical excision may prevent future neurologic deficits.