Neurology cases: Bing-Neel syndrome: a rare imitator of secondary normal-stress hydrocephalus

An 80-year-old man in remission with Waldenström macroglobulinemia (WM) presents with cognitive decline, broad-based shuffling gait and nocturia
.
Continuous head CT shows progressive ventricular enlargement
.
MRI shows fluid attenuation reversal of abnormal signals in lateral ventricles and peripheral sulcus/basal pools with fluid-fluid levels
.
Dura mater thickening/strengthening is seen in the frontal dura mater, cavernous sinus, and Meckel cavity (figure).

MRI of the spine shows strengthening along the thoracic spinal cord/conus with cauda equina thickening
.
Lumbar puncture showed a significant increase in cerebrospinal fluid protein (7.
01g/L) and the formation of jelly-like precipitate (video).

The number of cerebrospinal fluid leukocytes was 27×10^6/L (92% lymphocytes), and flow cytometry analysis confirmed recurrent central nervous system WM (Bing-Neel syndrome).

(Figure: A-B: CT confirms progressive ventricular enlargement; C: fluid decay reversal recovery sequence shows high intensification of fluid-fluid levels in the subarachnoid space and lateral ventricles; D: Contrast-enhanced T1 showed cavernous sinus thickening/strengthening[*]; E: T2WI can be seen with horsetail thickening; F: Spherical sediment in cerebrospinal fluid[*])