[Intravascular malignant lymphomatosis (IML) as a cause of cryptogenic stroke].

IML as one of the causes of cryptogenic stroke was nevieued in terms of the clinical features, diagnosis and treatment of IML. IML is a rare type of lymphoma which primarily proliferates inside blood vessels, caused mostly by B-cell type lymphocytes and rarely by T-cell type lymphocytes. IML has been difficult to be diagnosed antemortem because of nonspecific clinical and laboratory abnormalities, and has carried a poor prognosis. However, recent observations show that systemic chemotherapy may improve the outcome of IML in some patients, so that it is important to diagnose IML early and to initiate its treatment. We should consider the possibility of IML, if patients showed one or any combination of the following progressive four neurological features of undetermined etiology: 1) subacute multifocal cerebral infarcts, 2) paraparesis, 3) subacute encephalopathy, and 4) mononeuropathy to multiple mononeuropathy, particularly if patients showed an elevation of serum LDH and soluble interleukin-2R values, albuminocytologic dissociation in the cerebrospinal fluid, or any of the 3 abnormalities. If the possibility of IML is present, we should perform biopsies in involved areas such as skin, skeletal muscle and brain. Recent reports also show that polymerase chain reaction test of B-type lymphocytes in the peripheral blood is also helpful, involving the immunoglobulin heavy chain gene variable region. Early diagnosis and early treatment by vigorous chemotherapy such as biweekly CHOP therapy may improve the outcome of IML.