Giant serpentine aneurysm.

To cite: Grandhi R, Williamson RW, Zwagerman NT, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2015212019 DESCRIPTION A 34-year-old man with a history of seizures presented after a generalised seizure. An MRI of the brain and MR angiogram of the brain (figure 1) were performed, demonstrating a partially thrombosed, giant intracranial aneurysm involving the left anterior cerebral artery (ACA). The patient underwent a diagnostic cerebral angiogram (DCA) revealing a 4 cm serpentine aneurysm of the left ACA (figure 2). A balloon-test occlusion (BTO) was subsequently performed within the left ACA, proximal to the aneurysm; no changes manifested to the patient’s clinical examination. He subsequently underwent a craniotomy with trapping of the giant aneurysm and aneurysmorrhaphy. Intraoperative angiography confirmed obliteration of the aneurysm. Following discharge, he no longer experienced seizures. Giant serpentine aneurysms (GSAs) are extremely rare, and defined as ≥25 mm in size. First described by Segal in 1977, they are characterised by the presence of significant intraluminal thrombus and a snake-like channel between the inflow and outflow of the aneurysm. GSAs are most commonly associated with the middle cerebral artery, with the literature documenting very few involving the ACA. A number of modalities for treatment of GSAs exist: open surgical approaches include proximal and/or distal clipping (sometimes requiring an intracranial bypass), aneurysm resection/reconstruction, or carotid ligation, while endovascular techniques range from parent artery sacrifice to direct embolisation of the GSA with coils or liquid embolic agents. A key aspect in the evaluation of a patient with such pathology involves performing a DCA and BTO to determine whether the parent artery can be sacrificed.