[Intravascular lymphomatosis manifesting clinically as subacute encephalopathy]

We report a 62-year-old woman with intravascular lymphomatosis (IVL) which presented as subacute encephalopathy. She was admitted to our hospital because of loss of consciousness in the middle of February, 2006. Laboratory tests indicated elevated serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and cerebrospinal fluid protein. Magnetic resonance imaging (MRI) of the brain revealed multiple infarct-like lesions mainly in the white matter. After admission, her consciousness was soon improved, but the inflammatory response did not disappear with any antibiotics or virucides. Her consciousness was not exacerbated, and she was discharged in the middle of March, although the reason for loss of consciousness remained unknown. After discharge she developed an abnormal behavior and mental deterioration, and therefore she was readmitted late in March. On second admission, her consciousness was drowsy. Neurological examinations revealed conjugate deviation of her eyes to the left, left hemiparesis, and generalized hyporeflexia. Laboratory tests showed more elevated CRP than that of the last time, and raised soluble IL-2 receptor (sIL-2R). The repeated MRI of the brain disclosed that initial lesions of the white matter progressively enlarged and increased in number. To make an appropriate diagnosis of the lesions on the brain MRI, the open brain biopsy was performed. Microscopic examination showed that many small vessels were occluded by lymphoma cells (B-lymphocytes) with hemorrhage, and IVL was diagnosed. She was treated with regimens of combined chemotherapy with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone). After chemotherapy her consciousness and left hemiparesis were gradually improved and the levels of CRP were normalized. The infarcts-like lesions detected on the brain MRI became reduced and decreased. IVL is a rare disease, and the prognosis is generally poor, with a rapidly fatal outcome, leading to a postmortem diagnosis. In the present report, we successfully treated the patient by rituximab in addition to standard CHOP therapy. Rituximab may play an important role in the treatment of IVL.