Table 3 Criteria which should raise clinical suspicion for PCNSL and sentinel demyelination in patients with white matter lesions

Clinical

• Middle to older age with no prior clinical episodes or radiographic lesions suggestive of MS

• Rapidly deteriorating course

• Steroid dependence

• Lack of spinal cord involvement

Imaging

• Increased enhancement or lesion size over time

• Disproportionate mass effect

CSF

• Abnormal cytology (clonal IgG gene rearrangement)

• No oligoclonal bands