Typical "brainstem chocolate chip sign" in heterozygous HTRA1-related cerebral small vessel disease.

We report a 59-year-old man with heterozygous HTRA1-related cerebral small vessel disease (hHTRA1-CSVD) presenting with vascular dementia and gait disturbances. Susceptibility-weighted imaging revealed multiple round or ovoid hypointensities around the midbrain, pons, and medulla-termed the "brainstem chocolate chip sign." This feature may represent leptomeningeal venous abnormalities and may serve as a specific imaging marker for hHTRA1-CSVD.