CNS tumor
Lymphoma and other hematopoietic lesions
Primary CNS lymphoma

Author: Nat Pernick, M.D. (see Authors page)

Revised: 7 September 2017, last major update January 2006

Copyright: (c) 2002-2017,, Inc.

PubMed Search: Primary CNS lymphoma [title]

Cite this page: Pernick, N. Primary CNS lymphoma. website. Accessed June 20th, 2018.
Definition / general
  • Formerly called reticulum cell sarcoma or diffuse histiocytic lymphoma
  • By definition, occurs first in CNS without evidence of systemic lymphoma
  • < 2% of brain tumors
  • Usually in cerebrum but also elsewhere
  • May develop subsequent systemic lymphoma
  • Increased incidence (1000x) with AIDS and immunosuppression; also older immunocompetent patients
  • Most are high grade, diffuse large B cell lymphoma
  • Other subtypes are rare (plasmacytoma, angiotropic lymphoma, Hodgkin lymphoma, MALT)
  • High incidence of T cell subtypes in Korea (17%, similar in Japan, vs. < 5% elsewhere, Am J Surg Pathol 2003;27:919)
  • Steroid pretreatment causes necrosis and makes diagnosis difficult
  • Pathogenesis uncertain since CNS lacks a regular lymphatic system
  • In previously healthy individuals, arise at age 50+ years, 60% male vs. mean age 10 years with inherited immunodeficiency, 37 years for transplant recipients, 39 years for AIDS patients
  • Often present with focal neurologic deficits (50 - 80%), neuropsychiatric symptoms (20 - 30%), increased intracranial pressure (10 - 30%), seizures (5 - 20%), eye symptoms (5 - 20%)
  • Usually discrete masses
  • Rarely presents as diffuse, infiltrating condition without a cohesive mass, called lymphomatosis cerebri, associated with rapidly progressive dementia (Hum Pathol 2005;36:282)
  • CSF cytology helpful in diagnosing lymphoma of dura, leptomeningeal space or nerve roots
Radiology description
  • Bilateral, symmetric, subependymal, high signal foci on CT / MRI are suggestive
  • AIDS cases have multifocal, ring enhancing lesions with central necrosis, resembling toxoplasmosis
Poor prognostic factors
  • Multiple lesions, periventricular or meningeal involvement, associated immunodeficiency, age 60+ years, preoperative Karnofsky score 70 or less (J Clin Oncol 2003;21:266)
  • Expression of p53, c-Myc or bcl6 in immunocompetent patients in one study (Arch Pathol Lab Med 2003;127:208)
  • Survival:
    • In immunocompetent patients treated with radiotherapy and chemotherapy, 2 year overall survival is 40 - 75% and 5 year overall survival is 25 - 45%
    • AIDS patients have median survival of 2 - 6 months, increasing to 13 months with multimodal therapy
Case reports
  • Radiotherapy and chemotherapy
Gross description
  • Single or multiple, discrete or infiltrative, often deep seated and periventricular
  • Tissue may be variegated, friable, granular, necrotic, hemorrhagic, gray tan and resemble infarct or glioblastoma
  • Tumors of dura mimic meningioma
Microscopic (histologic) images

Images hosted on other servers:


CD20+, c-Myc+, p53+, bcl6+

Differential diagnosis
  • Demyelinating disorder: macrophage rich with preservation of axons
  • Glioblastoma: more nuclear and cellular pleomorphism, vascular proliferation, necrosis with pseudopalisading of tumor cells, GFAP+, CD45-, CD20-
  • Infarct: macrophage rich, axonal destruction
  • Inflammatory lesions
  • Metastatic carcinoma: more cohesive, no perivascular deposition, keratin+, CD45-, CD20-
  • Metastatic lymphoma: tumor outside CNS