Abstract

Background: Epidermal inclusion (epidermoid) cysts are rare benign intracranial lesions that account for less than 1% of all intracranial tumors. Their occurrence within the fourth ventricle is exceptionally uncommon and may lead to significant mass-effect symptoms. Case Presentation: A 45-year-old female presented with a one-year history of intermittent headache with recent worsening, followed by progressive vertigo and projectile vomiting. Neuroimaging (CT and MRI) demonstrated a wellcircumscribed cystic lesion occupying the fourth ventricle with extension into the bilateral cerebellar hemispheres and foramina of Luschka and Magendie, producing marked compression of the pons, medulla, and cerebellar hemispheres. The lesion was surgically excised. Histopathological examination revealed a cyst lined by stratified squamous epithelium containing abundant keratin flakes, confirming the diagnosis of an epidermal inclusion cyst. The postoperative period was uneventful, and the patient experienced complete resolution of symptoms. Conclusion: Fourth ventricular epidermal inclusion cysts are rare lesions that may mimic other posterior fossa tumors. Radiological features combined with histopathological evaluation are essential for accurate diagnosis. Surgical excision remains the treatment of choice and is associated with favourable outcomes when critical neurovascular structures are preserved.

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