Life-threatening exacerbation of a chronic porencephalic cyst in an adult: A case report and literature review.

Background: Porencephalic cysts are rare cerebrospinal fluid-filled cavities within the brain parenchyma, classified as either congenital or acquired (secondary to trauma, surgical interventions, ischemia, or infections). Clinical presentations vary depending on the cyst's size, location, and associated mass effect, with diagnosis established through neuroimaging. This report describes a rare, life-threatening exacerbation of a chronic porencephalic cyst in an adult, progressing to hydrocephalus and acute intracranial hypertension (IH). Case Description: A 57-year-old female presented to an outpatient clinic with an 8-month history of gait disturbances, memory impairment, apathy-abulia, and wheelchair dependence. Eight years earlier, she had sustained a mild traumatic brain injury, during which a porencephalic cyst was incidentally detected on cranial computed tomography (CT) scan; however, she had not been followed up, and the finding was not disclosed during the current evaluation. A new cranial CT and magnetic resonance imaging revealed a large porencephalic cyst in the left frontal lobe with mass effect, bilateral foramen of Monro obstruction, and hydrocephalus. An elective endoscopic cyst-ventricle communication was planned. Two weeks later, the patient presented signs of acute IH, including severe headache, diplopia, and blurred vision. An emergent external ventricular drain (EVD) was placed into the cyst cavity, leading to rapid symptom relief. The EVD was subsequently replaced by a cyst-peritoneal shunt. One year later, the proximal catheter became exposed and required complete shunt removal. Since then, she has remained clinically stable and shunt free. Conclusion: This case represents a rare, adult-onset, life-threatening exacerbation of chronic porencephaly. It demonstrates the importance of long-term follow-up in patients with known porencephalic cysts, even if previously asymptomatic, and the efficacy of timely neurosurgical intervention and close radiological monitoring in preventing severe or potentially fatal complications.