Bone wax can cause foreign body granuloma in the medulla oblongata.

Bone wax is commonly used in neurosurgical practice as a haemostatic and sealing agent. It is a safe agent, but may lead to adverse effects such as infection, epistaxsis, allergic reaction or foreign body granuloma. There are very few reported cases of the neurological complications of remnant bone wax in the subdural or subarachnoid space. The authors report the case of a foreign body granuloma infiltration through the medulla oblongata due to remnant bone wax in the subarachnoid space after posterior fossa decompressive surgery.