[A case of intravascular malignant lymphomatosis presenting as cerebral infarction].

A case of intravascular malignant lymphomatosis (IML) presenting as progressive cerebral infarction is reported. A 62-year-old previously healthy male developed progressive dementia. MRI of the brain at the nearest hospital revealed multiple infarcts with unknown etiology. His level of consciousness deteriorated rapidly, and then he was transferred to our hospital for further evaluation. High grade fever, raised serum C reactive protein (CRP), and raised lymphoma markers (serum LDH and soluble IL-2 receptor (sIL-2R)) were observed. Repeated brain MRI disclosed progression of multifocal cerebral infarctions. We considered IML most likely, and we performed muscle biopsy. However muscle biopsy didn't demonstrate any proliferation of neoplastic cells of lymphoid origin within small vessels. Thereafter IML was diagnosed by brain biopsy. The patient underwent chemotherapy, but died of pneumonia due to severe myelosuppression. IML is a rare disease but most commonly shows neurological symptomatology as its clinical manifestation. Dementia is the most common neurological symptom, and progressive multiple infarction is the most common of the MRI findings. Rapidly progressive dementia associated with multiple infarction, when elevated CRP, LDH and sIL-2R are observed in the laboratory data, is suggestive of IML.