Intradiploic leptomeningeal cyst in an adult: role of percutaneous contrast injection in dural defect demonstration.

Leptomeningeal cysts are commonly seen in children usually following trauma and associated with bulging leptomeninges at the site of fracture. Intradiploic leptomeningeal cyst is an important differential for an expansile lytic lesion in the bony calvarium especially in a patient with a previous history of trauma. Here we present a case of intradiploic leptomeningeal cyst and describe the usefulness of retrograde cisternogram by CT-guided direct percutaneous cyst puncture where a CT cisternogram after intrathecal contrast injection could not demonstrate the dural defect and communication of the subarachnoid space with the intradiploic leptomeningeal cyst.