Secondary CNS lymphoma (SCNSL) refers to central nervous system spread of a lymphoma that originated elsewhere (in contrast to primary CNS lymphoma). It is typically a non-Hodgkin lymphoma, and maybe an isolated recurrence or may be part of a systemic disease at the time of presentation 2. Unlike primary CNS lymphoma, it more commonly involves the leptomeninges and is uncommonly detectable on CT/MRI, with malignant cells found on CSF aspiration.
Leptomeningeal lymphoma accounts for two-thirds of cases of secondary CNS lymphomas, the remaining third presenting like primary CNS lymphomas (parenchymal disease).
The histological grade of the primary lymphoma influences the risk of developing secondary CNS lymphoma: if the primary lymphoma is classified as indolent, aggressive, or highly aggressive, there is a 3%, 9%, and 27% risk, respectively, of developing SCNSL 2.
Secondary CNS lymphoma can manifest with a new-onset headache, cranial nerves palsies (especially the III, IV, VI, and VII nerves), changes in mental status, and even coma and seizures 2.
Secondary CNS lymphoma can be divided into those with leptomeningeal involvement, the most common form, those with parenchymal involvement, or as a combination of the two 2.
Risk factors for secondary CNS lymphoma are 2:
- the variant of primary lymphoma
- involvement of more than one extranodal site
- serum lactate dehydrogenase level greater than three times the normal limit
- advanced stage of the systemic disease
- high international prognostic index
Contrast-enhanced MRI is the modality of choice. Imaging features of leptomeningeal secondary CNS lymphoma include leptomeningeal, dural, subependymal and cranial nerve enhancement. Communicating hydrocephalus may be present.
Parenchymal secondary CNS lymphoma appears quite similar to primary CNS lymphoma, however, it can be accompanied by leptomeningeal and subependymal enhancement.
- 1. Haldorsen IS, Espeland A, Larsson EM. Central nervous system lymphoma: characteristic findings on traditional and advanced imaging. AJNR Am J Neuroradiol. 2011;32 (6): 984-92. AJNR Am J Neuroradiol (full text) - doi:10.3174/ajnr.A2171 - Pubmed citation
- 2. DeRosa P, Cappuzzo JM, Sherman JH. Isolated recurrence of secondary CNS lymphoma: case report and literature review. J Neurol Surg Rep. 2014;75 (01): e154-9. doi:10.1055/s-0034-1378152 - Free text at pubmed - Pubmed citation
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