Prevalence: 3.3% of CNS lymphoma, 1% of all lymphomas

Mean age: 47 years; M<F

Histo: monotonous collection of lymphocytes packed tightly into perivascular space; predominantly B-cell lymphocyte population; no necrosis

• weakness, numbness, progressive difficulty in ambulation

Location: cervical >thoracic >lumbar cord

Site: in extradural compartment (most commonly)

MR:

• mostly solitary, rarely multicentric
• isointense relative to cord on T1WI
• hypointense with cord on T2WI (related to high nuclear-to-cytoplasmic ratio)
• extensive cord edema
• hetero- / robust homogeneous enhancement
• restricted diffusion ← high cellularity + reduced extracellular matrix

Cx: compression of cord due to narrowing of spinal canal

Rx: initial response to steroids; radiation therapy results in rapid reduction in size + compressive effects