Two new cases of leptomeningeal cysts subsequent to vacuum extraction are reported. Both children presented with a huge, nonpulsating, transilluminating subgaleal collection over the anterior fontanel that appeared soon after instrument delivery. Plain X-rays, computed tomography, and magnetic resonance imaging confirmed that the subgaleal collection was cerebrospinal fluid and showed the presence of a diastatic coronal suture in both cases. Treatment consisted of duraplasty with periosteal flaps and application of fibrin glue. In one case, an associated porencephalic cyst was treated with a cystoperitoneal shunt. Surgical treatment of leptomeningeal cyst due to vacuum extraction is simple and should not be postponed, despite the tendency for the extracranial cyst to regress, because of the potential risk of continuous growth of an underlying porencephalic cyst and risk of neurological damage.