Central nervous system complications in patients with diffuse histiocytic and undifferentiated lymphoma: leukemia revisited.

Fifteen of 52 patients (29%) with diffuse histiocytic and undifferentiated pleomorphic lymphoma developed central nervous system (CNS) complications, primarily leptomeningeal lymphoma. Lumbar puncture with cerebrospinal fluid cytology was the most useful test for diagnosis, and for following the response to therapy. Leptomeningitis developed during all stages of the patients' clinical course: at time of diagnosis, during progression of systemic disease, and most importantly as the initial site of relapse within 7 mo of attaining a complete clinical remission. Patients with bone marrow involvement are at high risk for the development of leptomeningeal lymphoma. Pathologic findings suggest that entry into the leptomeninges involves extension from the medullary bone marrow cavity along perforating vessels through dura into the arachnoid space. The leptomeningeal lymphoma has been successfully controlled in all patients receiving intensive central nervous system therapy consisting of a combination of intrathecal drug administration and radiotherapy. The high frequency of this syndrome and the success in its control suggest that a controlled trial of prophylactic CNS therapy be instituted in patients with these histologic types of non-Hodgkin's lymphomas.