Double paramedian occipital dermal sinus revealing an infected intra-dural dermoid cyst of the posterior cerebral fossa: Case report

Background: Intracranial dermoid cysts (DC) are rare benign embryologic tumors. They represent approximately 0.3% of all intracranial tumors. The association of intracranial DC and multiple dermal sinuses is exceptional. Methods: A 3 year-old girl presented with headache and vomiting. Physical examination showed nothing abnormal except for a small subcutaneous nodule above the occipital protuberance with a small skin opening. She had no neurological deficits. MRI and CT scan showed a cyst in the posterior fossa with occipital sinuses. The child was treated by total resection of the intra-dural occipital cyst and the abscess though a suboccipital approach and antibiotics after surgery with good outcome. Results: Histopathologic examination confirmed a diagnosis of DC, and bacterial investigation of the abscess did not yield any microbes. Conclusion: Infected Intradural DC with complete dermal sinus is a rare type. Radical neurosurgical treatment of DC and dermal sinus associated with antibiotics should be planned early to prevent infections such as abscess and meningitis. Keywords: Dermoid cyst, Dermal sinus, Intradural, Cerebral posterior foss