Giant intradiploic arachnoid cyst for 13 years

A case of intradiploic arachnoid cyst is reported. The patient presented with a progressively enlarging swelling situated over left frontal region for approximately 13-years following blunt trauma to head. Magnetic resonance imaging showed an intradiploic fluid containing cyst having intensity like cerebrospinal fluid (CSF). He underwent craniotomy and successful surgical repair. Intraoperatively CSF cyst was located in the frontal pole with a large defect over inner table and large rent in the dura. It was lined with arachnoid membrane. Pertinent literature is reviewed in brief.