A 14-year-old girl presented with developmental delay and dysmorphism at age 18 months. Chromosomal microarray showed loss of copy in the subtelomeric region of chromosome 9q confirming the diagnosis of KS. At age 23 months, MRI showed ventriculomegaly. Seizures started at age 10 years. Follow-up MRI showed cerebrospinal fluid (CSF) dissection from the right lateral ventricle which progressed similarly to the contralateral side four years later. To date there are 100 reports of KS, and most with limited neuroimaging data and a wide range of findings from normal anatomy to hypoplasia of cerebral structures associated with ventriculomegaly to white matter changes. However, there is only one report with longitudinal MRI findings showing reversible white matter changes in this disorder. Instead, our patient’s longitudinal MRI findings revealed progressive development of CSF dissection, which remained stable on subsequent MRIs.