The incidence of central nervous system leukemia in adults with acute leukemia

To determine the incidence of central nervous system leukemia (CNSL) in adults with acute leukemia (AL) we studied 299 patients admitted from 1966 to 1971, and reviewed 170 autopsies from that group. CNSL was diagnosed clinically in 38 of 299 (13%) patients, with a higher incidence in acute lymphocytic leukemia (ALL) and acute undifferentiated leukemia (AUL) and a lower incidence in acute myeloblastic leukemia (AML) and acute blastic crisis of chronic myelocytic leukemia (CML‐ABC). Autopsy evidence of CNSL was found in 43 of 170 (25%) evaluable autopsies with a higher incidence in ALL, AUL, and CML‐ABC, and a lower incidence in AML. The incidence of CNSL is related to morphological type, age, sex, survival, and responsiveness to chemotherapy. Arachnoidal infiltration was associated with a higher incidence of other pathologic manifestations of CNSL and extramedullary leukemic infiltrations. CNSL is common enough in adult AL to warrant aggressive diagnostic, therapeutic, and prophylactic measures.