BACKGROUND: The intradiploic arachnoid cysts are rare entities, which aregenerally post-traumatic and occur mostly in occipital region.
CASE DESCRIPTION: A 64-year-old woman was diagnosed with nontraumatic intradiploic arachnoid cyst. Her complaint was growing swelling on the forehead three years ago. As the operative findings, the small dural defect was recognized and arachnoid tissue in the cyst wall. Extradural intracranial arachnoid cyst without trauma is very rare.
DISCUSSION AND CONCLUSION: The intradiploic arachnoid cysts are thought to occur due to small defects in the dural membrane. Therefore, it seems that the region of the intradiploic arachnoid cysts depend on that of the dural membrane defects.
