Association of monocytic leukemia in patients with extreme leukocytosis.

Fifteen of 73 newly diagnosed patients with acute myeloid leukemia (AML), admitted to Mount Sinai Hospital between July 1977 and October 1979, presented with leukocyte counts greater than 100,000/microliter. Eleven of these 15 patients with hyperleukocytosis had myelomonocytic (AMML-M4) or monocytic (AMOL-M5) leukemia compared to 15 of 58 patients with lower white cell counts (p < 0.001). Identification of type of leukemia, using the FAB classification, was based on morphology and special stains, including myeloperoxidase, Sudan black B, periodic acid-Schiff and nonspecific esterase with and without inhibition by fluoride. The proportion of patients with splenomegaly is higher in those with hyperleukocytosis (73 percent) than in those with lower white blood cell counts (p < 0.001) regardless of cell type. Leukemic infiltration of the skin, gums and central nervous system was seen exclusively in patients with AMML and AMOL. The serum lysozyme levels were significantly higher for all patients with AMML and AMOL regardless of the white blood cell count. The mean serum lysozyme for M-4, M-5 patients was 59.7 microgram/ml compared to 18.9 microgram/ml in patients with other cell types (p < 0.0001). Patients with a white blood cell count less than or equal to 100,000/microliter had a complete remission rate of 69 percent compared to 47 percent for patients with higher white blood cell counts.