Pathogenesis of central nervous system infiltration in acute leukemia.

The distribution pattern of leukemic infiltrates was studied in 31 cases of acute leukemia with CNS involvement. Dura mater involvement was found in 93% (29/31) of the cases; arachnoid, 71% (22/31); perivascular cuffing, 37% (17/31); parenchymatous, 16% (5/31). Dura matter infiltrates were the sole manifestation in nine cases; Infiltration of the arachnoid in the absence of dural infiltration was rare (9%). The anatomic evidence supports the concept that leukemic cells infiltrate by way of perivenous adventitial tissue connecting the dura mater and subarachnoid space. It is likely that this pathway leads directly from the bones of the skull into the brain parenchyma.