A 16-year-old patient with no previous medical history, presenting with a progressive neurological disorder characterized by balance disturbance and binocular diplopia. Physical examination showed dysarthria, pyramidal syndrome, action tremor, and pseudo-folliculitis.

The cerebral magnetic resonance imaging (MRI) showed a bilateral asymmetrical high T2 signal of the posterior arms of the internal capsules associated with bilateral T2 and flair hyperintensity of the mesencephalon (figure 1). The high signal involvement of the mesencephalic junction is defined as a waterfall or cascade sign (figure 2).

Fig. 1.

Sagittal view of brain RMI showing with bilateral T2 and flair hyperintensity of the mesencephalon.

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Fig. 2.

Coronal brain RMI T2 high signal involvement of the thalamus: Cascade sign.

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Cerebrospinal fluid was inflammatory with an aseptic lymphocytosis (238 cells/mm3) and matched oligoclonal bands.

Medical history was reconducted. The patient confirmed recurrent aphthous that she neglected. Behçet's disease was diagnosed according to EULAR criteria (oral recurrent aphthous, skin, and neurological involvement).