Improbable discovery of an incidental high-grade AVM: illustrative case

The authors discuss the first reported case of a large, high-grade arteriovenous malformation (AVM) in the dominant hemisphere, discovered incidentally after a penetrating nail gun injury.

The patient underwent surgical removal of a nail lodged in the right frontal lobe. A contralateral AVM was diagnosed on his perioperative imaging and was evaluated further with diagnostic cerebral angiography. Because of the location of the AVM within the dominant fronto-opercular region, the patient underwent a super-selective Wada test to evaluate for the risk of expressive language deficit prior to undergoing a successful resection of the AVM. He had an excellent recovery from both surgeries without any neurological deficits.

This case illustrates the importance of continued suspicion for incidental findings when reviewing imaging, despite the presence of a known and obvious pathology. The observations add nuance to the standard considerations for surgical intervention for penetrating nail gun injuries, and the workup for incidentally found vascular lesions is reviewed. https://thejns.org/doi/10.3171/CASE24850.