Central Nervous System Involvement in Peripheral T Cell Lymphoma.

PURPOSE OF REVIEW: Central nervous system (CNS) involvement in peripheral T cell lymphoma (PTCL) is a difficult condition to treat, both as a primary and a secondary disease.

RECENT FINDINGS: Primary CNS lymphoma (PCNSL) in PTCL is very rare, making up only 2% of all PCNSLs. The incidence of CNS relapse is generally 2-6% in all cases of PTCL, but the risk may vary by histologic subtype, and extranodal involvement > 1 has been consistently found to be a risk factor for CNS relapse. Currently, there is no consensus about indications for CNS prophylactic treatment. A high-dose systemic methotrexate-based regimen is the most commonly used treatment, with or without consolidation with high-dose chemotherapy with autologous stem cell transplantation for both primary and secondary CNS involvement. This approach, however, is generally toxic for older patients. New therapeutic approaches against PTCL are therefore needed.