Case history
A 15-year-old girl was transferred from a primary care institution for
headache, acute left hemiparesis, and left paresthesia. Her history
revealed left hypoacusis, left voice cord palsy, and left unreactive
mydriasis of unknown origin for over a 3-year period. The admission
brain CT scanner had shown heterogeneous parenchymal damage within the
right side of the pons (not shown). Three years earlier, the girl
underwent brain magnetic resonance imaging (MRI), which was described as
normal.
The brain MRI at admission showed an heterogeneous T2/FLAIR hypersignal
on the right thalami, cerebral peduncle, midbrain, and pons, displaying
marked restriction of free water diffusivity featuring cytotoxic edema
on diffusion-weighted (DW) views. A few pontine subareas disclosed low
signal intensity on both T2 and diffusion weightings suggesting foci of
hemorrhagic transformation (figure 1). Other multiple lesions already
detectable on the MRI performed three years earlier, were present as
bilateral vestibular schwannomas, left trigeminal schwannoma, together
with a meningioma at the cranial vertex and a cervical cord ependymoma,
strongly suggesting a type 2 neurofibromatosis (NF2).
On Day 14, the left hemiparesis worsened, and the girl exhibited
swallowing difficulties and bilateral facial palsy. The MRI, carried out
on Day 18, revealed a progression of the right-sided pontine lesion with
persistent mosaicism of acute ischemic lesions with high T2/FLAIR signal
intensity with lowered apparent diffusion coefficient (ADC) and strongly
hypointense areas with susceptibility artifacts on gradient-echo
T2-weighted views featuring hemorrhagic transformation (figure 2).
From Day 20 onwards, the girl progressively developed a spastic
quadriplegia with pyramidal signs and a vesical globe; owing to her
bilateral facial palsy, she was not longer able to speak, whereas her
cognitive function was preserved. The diagnosis of a locked-in syndrome
was retained.
We reviewed the diagnostic differential of brainstem lesions (table 1)
and faced with this progressive lesion, a tumor was suspected, and
corticosteroids were initiated. But stereotactic biopsy wasn’t
contributive with pathological changes evocating necrosis.
Then, by reviewing the girl’s full medical record, the diagnosis of
brainstem ischemic syndrome was proposed, reflecting an uncommon medical
condition associated with NF2. Brain magnetic resonance angiography
(MRA), cardiac-carotid and vertebral ultrasonography, and hemostasis
evaluation were unremarkable. Aspirin treatment was initiated, and she
was transferred to a rehabilitation center. Three months later, she was
able to carry out head movements which helped her communicate, as well
as some arm movements.
The NF2 diagnosis had meanwhile been confirmed by revealing an
heterozygous pathogenic variant on NF2 gene, c.1376dup
(p.Glu460GlyfsTer35).