Infected Intradural Dermoid Cyst with Complete Dermal Sinus of Posterior Fossa.

Background: Intracranial dermoid cysts are benign embryologic tumors. They occur most often in children and young adults. Infected intradural dermoid cyst with complete dermal sinus of posterior fossa is rare. The main feature of this dermal sinus is the continuity from the intradural cyst through the occipital bone to the skin.

Methods: We report 2 cases of infected intradural dermoid cyst with complete dermal sinus of posterior fossa in children, with special attention to the clinical and anatomical features of this rare combination of anomalies.

Results: A 5-year-old boy presented with a midline cystic lesion responsible for triventricular hydrocephalus revealed by a cerebellar syndrome and a dermal sinus. The second case was a 36-month-old girl who had an occipital cystic lesion that was limited by a pseudo-wall with diffusion restriction revealed by a double dermal sinus. We inserted an external shunt to relieve the increased intracranial pressure then performed a suboccipital approach for excision followed by systemic antibiotic therapy. Both cases had satisfactory outcomes.

Conclusions: Infected intradural dermoid cyst with complete dermal sinus of posterior fossa is rare, and a double dermal sinus has not yet published, to our knowledge.