Late-Onset Status Epilepticus Associated With Isolated Leptomeningeal Angioma and Sturge-Weber Syndrome-Related GNA11 Pathogenic Variation

Co-author · Neurology · 2023

Late-Onset Status Epilepticus Associated With Isolated Leptomeningeal Angioma and Sturge-Weber Syndrome-Related GNA11 Pathogenic Variation

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Context

Sturge-Weber syndrome is a condition usually diagnosed in childhood.

This article reports the unusual case of a 61-year-old man with no prior neurological history who developed severe epileptic seizures known as status epilepticus.

These episodes were prolonged, difficult to control, and led to temporary neurological deficits such as weakness on one side of the body.

Brain imaging (MRI) revealed a leptomeningeal angioma, a vascular malformation located on the surface of the brain.

This type of lesion is typically associated with Sturge-Weber syndrome.


Why it matters

This case is notable because:

  • The patient had no classical features of the syndrome (no facial birthmark, no ocular involvement)
  • Symptoms appeared late in adulthood, which is highly unusual


What we found

Imaging showed focal hypoperfusion and localized cortical atrophy.

Histological findings revealed vascular abnormalities.

Histology of leptomeningeal angiomatosis showing enlarged veins

Leptomeningeal vascular abnormalities

Enlarged veins with angiomatosis.

Immunohistochemistry showing alpha-smooth muscle actin in vein wall

Abnormal smooth muscle actin expression

Abnormally expressed alpha-smooth muscle actin in vein wall.

Glomeruloid vessels in cortical layers II-III

Cortical glomeruloid vessels

Cortex (layers II–III): glomeruloid vessels without neuronal loss, gliosis, or calcification (×200–400).

CD34 immunostaining of glomeruloid cortical vessels

CD34 endothelial staining

CD34 staining of the glomeruloid vessels.

On the leptomeningeal biopsy, we identified a specific somatic mutation GNA11 R183C (VAF: 4%), previously known to be involved in Sturge-Weber syndrome.

Together, these findings support the diagnosis of type III Sturge-Weber syndrome.


Contribution to knowledge

This case shows that:

  • Sturge-Weber syndrome can exist without the full set of signs and symptoms
  • It can manifest later in life as severe epilepsy
  • It reinforces the role of genetic mutations, particularly somatic mutations, in these atypical forms

In practice, this suggests that some unexplained adult-onset epilepsies may have an underlying, underdiagnosed vascular-genetic origin.



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