Immunodeficiency-associated CNS lymphomas

Immunodeficiency-associated CNS lymphomas are recognized in the current (2016) WHO classification of CNS tumors as a specific subtype of primary CNS lymphoma. A number of further specific subtypes are recognized, including:

• AIDS-related diffuse large B-cell lymphoma
• EBV-positive diffuse large B-cell lymphoma, NOS
• lymphomatoid granulomatosis
• primary CNS posttransplant lymphoproliferative disorder

Pathology

In most instances, and unlike sporadic primary CNS lymphomas, these tumors are associated with prior EBV infection . They express EBER1, EBER2, LMP1 and EBNA1-6 .

Predisposing conditions

Essentially any cause of immunosuppression increases the risk of developing primary CNS lymphoma, including :

• iatrogenic immunodeficiency
  • azathioprine
  • methotrexate
  • mycophenolate
• congenital immunodeficiency syndromes
  • IgA deficiency
  • Wiskott-Aldrich syndrome
• acquired immunodeficiency syndromes
  • HIV/AIDS leading to AIDS-related diffuse large B-cell lymphoma
• autoimmune diseases
  • Sjogren's syndrome
  • systemic lupus erythematosus (SLE)

Radiographic features

Although generally, the features of immunodeficiency-associated CNS lymphomas is similar to that of sporadic primary CNS lymphomas, in the setting of immunodeficiency tumors are more likely to be:

• heterogeneous peripheral enhancement with central non-enhancement (due to necrosis). This is in contrast to solid homogeneous enhancement in immunocompetent lymphoma
• multifocal
• surrounded by a greater degree vasogenic edema