Chromosomes in the spinal fluid: evidence for metastatic origin of meningeal leukemia.

I T IS WELL KNOWN that the blastic cells in acute leukemia often show numerical or other aberrations from the normal karyotype, which permit their characterization as stem lines.13 While these may undergo further evolution, they generally remain identifiable during consecutive relapses throughout the course of the disease,4’5 thus constituting evidence for the persistence of an autonomous cell population. Thus far, chromosomal studies have been restricted to bone marrow and cultured blood cells. Except for a single report demonstrating the Ph1 chromosome in myeloblasts in the spinal fluid of a patient entering the blastic phase of chronic granulocytic leukemia,#{176} the cytogenetic aspects of leukemic cells in the central nervous system have not been investigated. Under current therapeutic conditions, between one third and one half of the children with acute leukemia show involvement of that system at some time. The origin of the leukemic cells in the spinal fluid has been the subject of speculation.71#{176} The demonstration of a chromosomal constitution common to these cells and the leukemic bone marrow population would greatly strengthen the evidence for their metastatic character. This report describes the cytogenetic findings in the spinal fluid of nine children with acute leukemia.