Symptomatic Expanding Porencephalic Cyst after Evacuation of Intracerebral Hematoma in an Adult: A Case Report.

Porencephalic cysts are very rare in adults. Herein, we present a case of an 88-year-old man with a symptomatic expanding porencephalic cyst after intracerebral hematoma evacuation. He was admitted because of disturbed consciousness and right hemiparesis. A computed tomography (CT) showed a large subcortical hematoma in the left parietal lobe. Hematoma evacuation was performed, his consciousness level improved but gradually deteriorated. Follow-up CT revealed a new cystic lesion with perifocal edema at the hematoma site, with progressive expansion of the cyst. Cyst drainage and -peritoneal shunt placement were performed on postoperative day 14; consequently, his symptoms improved. Considerably, a porencephalic cyst have developed because the cerebrospinal fluid flowed into the closed hematoma cavity from the ventricle owing to the osmotic pressure difference between the ventricle and the hematoma cavity.