Primary marginal zone lymphoma of the CNS presenting as a diffuse leptomeningeal process

Primary CNS (PCNS) lymphoma accounts for less than 3% of all primary brain tumors1; primary extranodal marginal zone B cell lymphoma of the CNS, which includes the mucosa-associated lymphoid tissue (MALT) lymphoma subtype, is extremely rare, comprising up to 5.4% of PCNS lymphomas.2 PCNS MALT lymphomas are localized, low-grade lesions that occur more frequently in women, often present with indolent neurologic symptoms and focal seizures, and manifest as meningioma-like dural-based discrete masses on neuroimaging.3,4 This case illustrates a novel presentation of a rare CNS malignancy.