Lymphoma. A, Axial T2-weighted image shows relatively low signal intensity of the mass indicating high cellularity (black arrow) with surrounding edema high signal intensity B, Postcontrast Tl-weighted image demonstrates marked enhancement of the mass in the right centrum semiovale with surrounding edema. (Click to magnify figure)
Secondary CNS lymphoma occurs from spread of systemic disease to the CNS (non- Hodgkin’s more common than Hodgkin’s). Secondary lymphomas typically involve the leptomeninges, and CSF with parenchymal involvement is much less common. MR imaging findings include leptomeningeal/dural enhancement and hydrocephalus.

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