Abstract

Congenital dermal sinus is sinus is any depression or tract lined with stratified squamous epithelium which apparently result from defective separation of the neuroectoderm from the epithelial ectoderm along the mid-dorsal aspect of the embryo between the third and fifth week of intrauterine life. It occurs most frequently in the lumbosacral region and the next in the occiput. This dermal sinus may extends all the way into the spinal canal or cranial cavity. Because of its persistent communication with the skin surface, such a sinus tract serves as a constant potential port of entry for infection into the central nervous system. We have experienced a case of occipital dermal sinus of 5 months old male baby, who was admitted to Catholic Medical CЦ픔?Ч퉘?or high fever, vomiting and a small palpale mass at the occipital scalp. Computed tomography showed a round low density lesion with ring enhancement in the posterior fossa. An operation was given to reveal sinus tract started at the skin and extended into the posterior fossa forming a cyst, 4㎝ in diameter, which was located between cerebellar hemispheres. The cyst was filled with a yellowish white cheesy material containing hairs. Microscopically, the cyst was lined by stratified squamous epithelium and appendageal structures such as hair follicles and sweat glands. The sinus tract was also lined with stratified squamous epithelium. Total excision of the cyst and dermal sinus tract was performed, and the postoperative course was uneventful.