Enterogenous cyst at the cerebellopontine angle in an adult: the diagnostic challenge in a rare case report

Introduction and Importance: Enterogenous cysts (ECs) are rare, benign lesions lined by mucin-secreting cuboidal or columnar epithelium that resemble gastrointestinal or respiratory tissue. They are more frequently found in the spinal axis than in the intracranial compartment and are believed to arise from endodermal displacement during embryogenesis. With the advancement of neuroimaging, incidental detection has increased, although their radiological appearance often mimics other cystic lesions, making preoperative diagnosis challenging. Case summary: A 44-year-old female presented with vertigo and headache for four weeks. Neurological examination revealed left-sided cerebellar dysfunction. MRI of the brain demonstrated a left cerebellopontine (CP) angle cystic lesion. The patient underwent complete microsurgical excision of the lesion, and histopathology confirmed the diagnosis of an enterogenous cyst. At three months of follow-up, her symptoms had completely resolved, and MRI showed no evidence of recurrence. Clinical discussion: Intracranial enterogenous cysts are exceptionally rare and may mimic arachnoid, epidermoid, or other cystic pathologies, complicating preoperative diagnosis. Histopathological confirmation remains the gold standard for diagnosis. Complete surgical excision offers the best outcome, although adherence to vital neurovascular structures may limit total resection and increase recurrence risk. Therefore, long-term radiological follow-up is essential, as recurrence can occur years after apparently successful surgery. Conclusion: Enterogenous cysts should be considered in the differential diagnosis of posterior fossa cystic lesions. Early identification, accurate diagnosis, and complete excision provide favourable outcomes, while continued follow-up is recommended to detect potential recurrence.