脳梗塞で発症した血管内悪性リンパ腫症の1例

A Case of Intravascular Malignant Lymphomatosis Presenting as Cerebral Infarction

I．はじめに

　血管内悪性リンパ腫症（intravascular malignant lymphomatosis；IML）は中枢神経，皮膚をはじめとして全身の諸臓器の血管内で腫瘍細胞が増殖する稀な疾患である^8,22）．その報告は1959年のPflegerらの報告^15）に遡り，腫瘍細胞の由来が血管内皮細胞であると考えられていたため，neopla-stic angioendotheliosis,angioendotheliomatosis，malignant angioendotheliomatosis,cerebral an-gioendotheliomatosisなどと呼ばれていた^10）．現在ではその腫瘍細胞は主にBリンパ球系細胞に由来し^{4,11,12,18）}，非ホジキンリンパ腫の1亜型であると考えられている．また，本疾患に特異的症状・所見は乏しく，症状の進行も急速で予後も不良であることから，生前の確定診断は困難である．

　今回筆者らは，進行性の痴呆で発症し，画像上多発性脳梗塞の所見を呈し，開頭生検術により診断確定し得たIMLの1例を経験したので，若干の文献的考察を加えて報告する．

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 proli-feration 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 manifesta-tion. 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 ele-vated CRP, LDH and sIL-2R are observed in the laboratory data, is suggestive of IML.