Primary central nervous system leukemia with a novel chromosomal translocation.

A case of central nervous system (CNS) leukemia with normal bone marrow, associated with a novel chromosomal abnormality, is described. A 58 year-old woman complained of hearing disturbance, severe headache and vomiting, and showed signs of meningeal irritation, as well as papilledema and bilateral dysacusis. Immature atypical cells were found in the cerebrospinal fluid (CSF) with elevated pressure, pleocytosis, increased protein and decreased glucose levels. She was diagnosed as having neoplastic meningitis. In spite of intensive investigations, including bone marrow puncture, malignancies were not found in organs other than intra-cranial site. The symptoms and CSF findings were temporarily improved with chemotherapy and irradiation, but she relapsed into neoplastic meningitis. The anaplastic cells in CSF were positive with CD45 by immunocytochemistry, and were positive by peroxidase staining. Thus, the anaplastic cells were considered to be myelocytic leukemic cells. Chromosomal analysis showed that these leukemic cells had a novel chromosomal abnormality: 46XX, 4q+, 10q-, 16q-. There has been no report of leukemic meningitis without bone marrow abnormalities. It is possible that this peculiar abnormal chromosome is related to the primary infiltration of the central nervous system. With this novel chromosomal abnormality, this case is important for considering the mechanism of primary leukemic meningitis.