Fatal ruptured occult arteriovenous malformation in a young adult: An autopsy case report

Abstract

Background: Brain arteriovenous malformations (AVMs) are congenital developmental disorders with unclear causative factors and pathogenic mechanisms. Various epigenetic factors may influence the development and rupture of AVMs. Ruptured AVMs may lead to poor outcomes. Therefore, the risk factors of AVM rupture and treatment strategies for unruptured AVMs should be explored. Herein, we report a case of a fatal ruptured AVM diagnosed by radiological and autopsy findings and review the literature regarding AVM treatment.

Case description: A 46-year-old man was brought to the hospital with sudden loss of consciousness while sitting on the edge of the bathtub. On examination, he was unconscious with poor breathing efforts. He was intubated and a brain CT scan was performed, which showed an intracerebral hemorrhage (ICH) adjacent to the right trigone with massive intraventricular hemorrhage (IVH) and subarachnoid hemorrhage (SAH). Contrast-enhanced CT scan showed abnormal vessels adjacent to the hematoma. He was diagnosed with ICH associated with IVH and SAH caused by a ruptured abnormal vascular lesion. He underwent external ventricular drainage to control the intracranial pressure. He remained unconscious and died 16 h after hospital admission. Autopsy was performed to identify the cause of ICH. Pathological sections showed a mass of blood vessels, measuring 20 × 10 × 10 mm in size, within the hematoma with a single drainer connecting to the transverse sinus. These blood vessels had variable size, shape, and wall thickness on microscopy. Some vessels had abnormal thickened walls with discontinuous elastic fibers. Based on the radiological and autopsy findings, an ICH secondary to SpetzlerMartin Grade I AVM was confirmed.

Conclusion: If the cause of ICH cannot be determined during a patient's life, autopsy may be performed to determine the pathophysiology of occult vascular lesions, including AVMs. Patients with AVMs may have moderate or no symptoms before and after rupture. Because deep AVMs fed by posterior circulation have high risk of bleeding, surgical intervention should be considered for these patients to prevent a poor outcome. Low-grade and paraventricular AVMs in a young adult may be successfully treated with multimodal surgery.

Keywords: Diagnostic imaging; Endovascular procedures; Hemorrhagic stroke; Intracranial arteriovenous malformation; Microsurgery.

Figure 1:

Brain CT of the patient. Noncontrast CT scan (a: axial and b: coronal views) showing hematoma adjacent to the right trigone, intraventricular hemorrhage, diffuse subarachnoid hemorrhage, edematous brain, and hydrocephalus. Contrast-enhanced CT scan in the axial view (c) showing abnormal vasculature with an artery originating from the right posterior cerebral artery (white arrow), vein draining into the right transverse sinus (black arrow), and hematoma (dotted arrow).

Figure 2:

Pathological findings of the patient. A coronal section of the fixed brain (a) showing subarachnoid hemorrhage at the brain surface and hematoma in the right parahippocampal area although close to the right trigonum (encircled in a), with blood extending into the lateral ventricles. A 20 × 10 × 10 mm mass of blood vessels (b). Staining with hematoxylin and eosin (c) and Elastica van Gieson (d) showing small blood vessels with variable size, shape, and wall thickness. Thin-walled vessels had the appearance similar to veins but contained elastic fibers, which confirmed that they were arteries (dotted arrow in d). Some vessels showed abnormal partially thickened walls with discontinuous elastic fibers (arrow in d).