Pathology of intravascular malignant lymphomatosis

On the basis of six necropsied cases of intravascular malignant lymphomatosis (IML), we elucidated its pathological characteristics. In the brain of IML, multiple softened areas of various size were observed, dominantly in the white matter of the cerebral hemisphere, which showed bilateral distribution with no relation to the supply area of the large vessels and intermingled fresh and old lesions. The spinal cord was one of the most often involved areas in IML, particularly at the lumbosacral segmental level. The origin of the tumor cells, based upon the findings that the tumor cell of all our cases were positive for SL-26, LN1, and LN2, were considered to be B-cell. We speculated that not only the circulatory failure due to the tumor cells which filled the vascular lumen, but also circulatory disturbances due to thrombosis, thickening of the intima and angiitis were significant findings for the necrosis in IML. IML is an important disease as the fourth type of central nervous system involvement due to malignant lymphoma, in addition to primary malignant lymphoma of the brain, meningeal lymphomatosis, compression of the spinal cord caused by extradural metastasis of lymphoma.