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Título

NON-DECUSSATION OF THE PYRAMIDAL TRACT DISCOVERED INCIDENTALLY IN AN ASYMPTOMATIC PATIENT WITH ARTERIOVENOUS MALFORMATION: CASE REPORT

RESUMO

INTRODUCTION: Abnormal pyramidal tract decussation is a very rare event
that can be seen in ectodermal dysplasias. Non-decussation of the pyramidal tract is
observed in several conditions such as Dandy Walker, Joubert, Kallman syndrome and
Ichthyosis. There are only a few case reports of incidental findings in healthy patients.
We describe a patient who exhibited hemiparesis ipsilateral to an arteriovenous
malformation (AVM) complication after embolization and whose neuroimaging showed
a lack of pyramidal tract decussation.
 
CASE PRESENTATION: A 47-year-old woman with a 5-month headache
history underwent neuroimage investigation with a CT scan that suggested an AVM at
the right parietal lobe. She had a clinical past of hypothyroidism denying previous
seizures or weakness. A neurological examination on admission revealed no focal
neurological deficit and the first brain magnetic resonance imaging (MRI) did not reveal
any parenchymal lesions. The patient underwent cerebral angiography, which revealed
AVM at the right angular gyrus and a 3-stage embolization was indicated. In the
postoperative of 3rd embolization session, the patient developed a right motor deficit
over the course of a few days. Brain MRI revealed a perilesional cytotoxic edema with
restricted-diffusion posteromedially to the AVM in the right parietal lobe – ipsilateral to
patient’s motor deficit. A 3.0 T MRI Tractography showed solely unilateral non-
crossing corticospinal tract with no decussation.
 
DISCUSSION: Pathologies of the pyramidal tract are rare and are frequently
associated with genetic and congenital disorders such as posterior fossa anomalies or
congenital mirror movements. However, they can be present in healthy, asymptomatic
individuals and observed when a lesion to motor areas causes ipsilateral motor deficits.
Only a few cases have been described in neurologic asymptomatic individuals. Our
patient presented with right-sided hemiparesis ipsilateral to an ischemic lesion after
AVM embolization.

Palavras Chave

Abnormal pyramidal tract; Arteriovenous malformation; Stroke