Diagnosis and treatment of a cerebellar arterio-venous malformation: a case report

Clinical History

A 17-year-old female patient, while in complete well-being, suddenly fell down to the ground unconscious and was transported to the emergency room. Physical examination was performed noting drowsiness, ataxia, vertigo and headache. These symptoms were suspicious for a stroke.

Imaging Findings

An emergency non-contrast CT documented an area of haemorrhage in the right cerebellum of 5 x 4 cm responsible of a mass effect on the brainstem and the fourth ventricle, associated with oedema and controlateral shift. After a CT angiography, we diagnosed a cerebellar AVM of 3.6 cm in the previous haemorrhagic area. Thus, an emergency craniectomy was performed to reduce the intracranial pressure through a CSF drainage. Non-contrast CTs after surgery showed a progressive reduction of the haemorrhagic and oedematous area, associated with a partial clinical resolution, despite the persisting AVM.

Discussion

AVMs are an abnormal tangle of arteries directly connected to veins without an intervening capillary network, that typically appear as a jumble of enlarged vessels without mass effect, in 90% of the cases in the supratentorial region. AVMs of the posterior fossa are relatively rare comprising only between 10 and 15 % [2]. Patients with posterior fossa AVMs are at increased risk for severe morbidity, mortality due to bleeding or complications related to procedures. Moreover, the annual risk of bleeding (2-3%) may double or even triple in the first year after an initial bleed [1]. Contrast-enhanced CT is the initial diagnostic examination to detect an AVM. MRI can be used to monitor the evolution. Non-contrast CT shows a mixed attenuation lesion, sometimes with evidence of calcification. MR demonstrates flow voids or complex flow patterns, sometimes leading to artefacts in the phase-encoding direction. However, angiography remains the definitive method for evaluation of the vessel anatomy and dynamic flow patterns. At the moment, several treatments are feasible: surgery, radiotherapy or endovascular embolization.
In our case we treated the lesion with an endovascular embolization.
Through a right retrograde transfemoral artery access, the internal carotid arteries and the vertebral arteries were selectively catheterized showing that the right AICA was the main feeding artery. Moreover, PICA was not a collateral of the AVM.
Thus, 6 cc of Glubran were injected in the feeding arteries. Post-procedural control documented the AVM complete exclusion.
MR after 30 days confirmed the complete exclusion of the AVM, with complete shift resolution and reduction of the haemorrhagic component.

Differential Diagnosis List

Final Diagnosis

Haemorrhagic stroke due to a cerebellar AVM.

URL:	https://eurorad.org/case/12796
DOI:	10.1594/EURORAD/CASE.12796
ISSN:	1563-4086