Intracranial Dermoid Cyst: Unusual Cause for Chronic Meningitis

Background: Dermoid cyst is a rare intracranial tumor that is usually asymptomatic. Symptomatic dermoid cysts can present with headaches, seizures, focal neurological deficits or features of hydrocephalus.

Clinical Presentation: A 57-year-old female patient presented with several episodes of severe headaches at a frequency of 2–3 events every year (for the preceding 5 years). These episodes usually lasted for several days and resolved with no specific treatment apart from analgesics. An MRI was performed during one of these episodes, and revealed a large heterogenous cystic lesion with calcification in the midline basifrontal region. This was associated with multiple small lesions within the subarachnoid spaces that were hyperintense on T1weighted MR images.

Intervention: The lesion was accessed through a right pterional craniotomy. While opening the dura, yellow droplets, suggestive of fat dissemination, were seen in the subarachnoid spaces. In the basifrontal region over the planum sphenoidale, an intradural pearly white cyst was found encased in a calcified capsule. The lesion was excised completely and the pathology confirmed the diagnosis of a dermoid cyst. The postoperative period was uneventful and the postoperative MRI showed no residual cyst. The patient remains asymptomatic at the latest follow up at 4 months after surgery.

Conclusion: Dermoid cysts can rarely present with episodes suggestive of chemical meningitis. We report the correlation between the clinico-radiological presentation and the intra-operative findings. Though rare, this diagnosis should be considered in patients presenting with clinical features of acute/chronic meningitis.