Corpus callosum granuloma after endovascular squid embolisation of a ruptured arteriovenous malformation

A late adolescent patient was admitted after a collapse and was found to have an intracranial haemorrhage due to an underlying midline arteriovenous malformation (AVM). The patient underwent trans-arterial squid embolisation of the AVM with good radiological resolution. 18 months later, the patient presented with new onset headaches. Cranial imaging demonstrated an enhancing lesion at the site of the previously thrombosed AVM in the corpus callosum. This was deemed to be a foreign body granuloma, a rare complication of intravascular embolisation of AVMs. The patient continued to have periodic imaging with subsequent scans demonstrating progressive changes in the granuloma and this was then resected surgically. We describe the natural history of the granuloma formation, outline the cranial imaging features associated with this rare condition and review the literature of similar cases.