Leptomeningeal infiltration in rat models for human acute myelocytic and lymphocytic leukemia

With respect to human leukemia, scarce data exist suggesting a difference in the leptomeningeal infiltration pattern between acute myelocytic leukemia (AML) and acute lymphocytic leukemia (ALL). In the present paper, the growth pattern of intrathecally inoculated AML and ALL in rat models is studied. It was observed that the leptomeningeal infiltration in ALL is more pronounced than in AML. In AML, no infiltration of the pia mater, ventricles or Virchow-Robin spaces were seen, in contrast to ALL, where these structures were infiltrated frequently. Both models were mimicking the pattern of leptomeningeal infiltration observed in the respective human leukemias. These animal models provide reproducible systems in which the determinants of metastatic capacity and their therapeutic implications for ALL and AML can be studied.