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).