Systemic vs. intrathecal central nervous system prophylaxis in primary adrenal/renal diffuse large b-cell LYMPHOMA: A multi-institution retrospective analysis and systematic review.

Primary adrenal lymphoma (PAL) and primary renal lymphoma (PRL) are rare extranodal lymphomas, predominantly of diffuse large B-cell lymphoma subtype. Primary adrenal and renal lymphomas (PARL) exhibit a high predilection for the central nervous system (CNS). Therefore, current guidelines support the use of CNS prophylaxis in PARL, particularly in cases of high-risk Central Nervous System International Prognostic Index (CNS-IPI). However, the route of administration (i.e. systemic vs. intrathecal chemotherapy) has not been clearly elucidated. With this in mind, we initiated an international collaboration and literature review to analyze 50 patient cases, 20 of which received CNS prophylaxis. Based on our analysis, we conclude that PARL may indicate a need for CNS chemo-prophylaxis in the form of systemic high-dose methotrexate (HD-MTX) over intrathecal methotrexate (IT-MTX), although IT-MTX may still have utility in certain cases.