Keywords
intracranial arteriovenous malformations - central nervous system vascular malformations
- therapeutic embolization - endovascular procedures
Palavras-chave
malformações arteriovenosas intracranianas - malformações vasculares do sistema nervoso
central - embolização terapêutica - procedimentos endovasculares
Introduction
Diffuse arteriovenous malformations (AVMs) of the central nervous system, also called
proliferative angiopathy (PA), are large lesions that can occupy an entire cerebral
hemisphere and cause mainly intractable seizures, motor deficits and other symptoms.
In PA, anomalous vessels continue to recruit additional feeder arteries,[1] making their architecture, natural history, clinical presentation and treatment
distinct from usual AVMs.[2] The cerebral PA is associated with the presence of a viable cerebral parenchyma,
in which it differs from usual AVMs and has important implications in the therapeutic
decision in patients with this rare vascular pathology.[2]
[3] Attempts to treat this condition are indicated in extreme cases, such as intractable
epileptic seizures, for example, although with great risks of aggravating the neurological
deficits.[2]
[4] We report a case of PA in an adolescent, its evolution and management regarding
clinical and imaging findings.
Case Report
A 15-year-old female patient presented with 5 years of headache and progressive right
hemiparesis. One year earlier, she had been admitted at her city's hospital after
generalized seizure and progressive drowsiness, and that was when she received the
misdiagnosis of brain AVM through a simple brain computed tomography (CT). An unsuccessful
embolization with n-butyl cyanoacrylate was attempted, evolving with cognitive worsening
and dysarthria. The patient was referred to our interventional neuroradiology department
presenting a proportionate right hemiparesis (muscle strength grade 4/5), spasticity,
postural instability, right ataxia; exacerbated deep appendicular reflexes on the
right side (grade 3/4), with plantar cutaneous reflex in extension bilaterally. The
cerebral digital subtraction angiography (DSA) ([Fig. 1]) showed the nidus of a bulky vascular malformation affecting the entire left hemisphere
fed by right anterior, middle and posterior cerebral arteries, and superficial venous
drainage (Spetzler-Martin grade V). No flow or intranidal aneurysms were identified.
An encephalic magnetic resonance image (MRI) ([Fig. 2]) evidenced an extensive vascular malformation with numerous ectasias and “flow void”
affecting the entire left hemisphere. We opted for conservative treatment with outpatient
follow-up and periodic control by imaging tests.
Fig. 1 Angiography. (a) RICA AP; (b) RICA RAO; (c) LICA AP; (d) LICA Lat; (e) LICA Lat late
phase; (f) RVA AP; (g) RVA Lat. Abbreviations: AP, anteroposterior; Lat, lateral;
LICA, left internal carotid artery; RAO, right anterior oblique; RICA, right internal
carotid artery; RVA, right vertebral artery.
Fig. 2 Resonance with extensive ectasias and “flow void” throughout the left hemisphere.
(a) axial T1 with contrast; (b) sagittal T1; (c) coronal T2.
Discussion
Cerebral PA has been described in a series of cases, predominantly affecting young
adult female patients, with onset of symptoms, on average, at 17 years-old and representing
∼ 3.4% of the diagnosed vascular malformations.[2] The most common form of clinical presentation are seizures; other less frequent
presentations are headache, intracranial hemorrhage and focal neurologic deficits.[2]
[3]
[5]
[6]
[7]
[8] The usual morphology on cerebral CT or MRI is characterized by diffuse vascular
lesions interspersed with normal brain parenchyma. The DSA of cerebral vessels does
not show dominance of a feeder artery; the nidus is generally larger than 6 cm with
difficult delimitation; and venous drainage does not have ectasia, in most cases.[2]
[3] In the histopathological analysis, the lesions are described as an intraparenchymal
vascular proliferation, with irregular and dilated arterioles but normal aspect and
veins with thickening due to collagen fibers.[2] The treatment must be considered according to the characteristics of histological
findings. Since those lesions are intermingled with healthy brain parenchyma, surgery,
radiotherapy and endovascular treatment have not been routinely recommended due to
the risk of permanent neurologic deficits already described in the literature. Invasive
techniques are reserved for cases of epilepsy and headache refractory to clinical
treatment.[2]
[5]
[8]
According to the literature, after an incorrect diagnosis and an unrecommended embolization,
there was worsening of the focal deficits.
Conclusion
The identification of cerebral PA as a distinct entity among other vascular malformations
is extremely important, since its natural history, treatment and prognosis are very
different from the usual and more frequent AVM.
