Endoscopic Treatment of a Midbrain Cyst: Case Report and Review of the Literature

Background and Importance: Midbrain arachnoid cysts are rare and usually present with symptoms associated with the mass effect or secondary hydrocephalus and require treatment. Because of their location, minimally invasive approaches using the endoscope are ideal since the open approach is difficult. Clinical Presentation: A 52-Years-old woman presented in the hospital for an acute confusional state and headaches. On examination, she had a partial Parinaud’s syndrome, and on history, she had been complaining of progressive diplopia for over two years. Imaging showed a large non-enhancing cystic lesion in the right mesencephalic-thalamic junction and descending to the cerebral peduncle, compressing the posterior aspect of the third ventricle and the aqueduct of Sylvius and responsible for secondary ventriculomegaly. She was treated with an endoscopic fenestration of the cyst, which leads to resolution of her symptoms. Conclusion: A contralateral endoscopic approach is a good minimally invasive technique for midbrain cysts, but such cases haven’t been widely reported. We discuss our case and provide a review of the literature showing good long-term outcomes when fenestrated into the ventricular system.