A Case of Congenital Dermal Sinus with Dermoid Cyst of Posterior Fossa

ABSTRACT

Congenital dermal sinuses are dermal tubes which extended inward from the surface for varying distances and frequently connect the central nervous system or its covering with the surface of the body. The inner end of the sinus may be expanded to form a dermoid or epidermoid cyst. They are the results of incomplete separation of the epithelial ectoderm from the neuroectoderm at the fourth week of fetal development. As cystic expansion of a congenital sinus which is located within the cranium or spinal canal may act as any other mass lesion to interrupt neurologic function by local compression or it may obstruct the normal circulation of spinal fluid. In addition, because of its persistent communication with the skin surface, it serves as a constant potential port of entry for infection into the central nervous system. Since the first report in 1926 by Moise of staphyloccus meningitis secondary to a congenital sacral sinus, numerous reports have appeared of infection secondary to congenital sinuses along the craniospinal axis, particulary in the suboccipital region. Authors report a case of congenital dermal sinus associated with dermoid cyst of posterior fossa which was successfully removed and discuss the pathegenesis of it in embryology, and surgical management of it's complications.