Bilateral retro-auricular dermal sinus tracts with intradural extension. Case report.

The authors describe a previously unreported malformation involving paired, bilaterally symmetrical dermal sinus tracts in the retro-auricular area, both of which passed through the asterion and posterior fossa dura mater to end intracranially. Cranial dermal sinus tracts are congenital lesions that virtually always originate from the midline scalp posteriorly at the external occipital protuberance, anteriorly at the nasion or along the nasal dorsum, or in the posterior parietal midline. A lateral origin is extremely rare, and intracranial extension of a lateral dermal sinus tract has not been reported previously. The authors propose an embryological mechanism to explain the origin of this rare malformation and discuss its management.