Child Neurology: A Case of Concurrent Neurofibromatosis Type 1 and Multiple Sclerosis by 2024 Criteria.

We present a female pediatric patient with known neurofibromatosis type 1 (NF1) whose surveillance imaging began showing multifocal periventricular and juxtacortical lesions with transient enhancement, initially attributed to NF1-related focal areas of signal intensity. Over time, the radiographic pattern raised concern for demyelinating disease. CSF studies revealed 10 unique oligoclonal bands. Despite the absence of neurologic symptoms, treatment with dimethyl fumarate was initiated and later transitioned to rituximab in the setting of ongoing active radiographic disease. Although the patient never developed clinical manifestations of demyelinating disease, updated diagnostic criteria now permit a diagnosis of multiple sclerosis. Central vein sign on MRI aided in differentiating radiographic features. This case illustrates how NF1 and demyelinating processes can have evolving and overlapping clinical and MRI features.