Excess leukocytosis (leukemoid reactions) associated with malignant diseases.

Twenty-one patients with malignancy had a peripheral white blood cell count of 50,000/cu mm or more. The malignancies arose from several tissues, especially lung; all were carcinomas except for one osteogenic sarcoma. In no case was there evidence of leukemia as defined by disorderly marrow growth, abnormal chromosomes, or abnormal leukocyte alkaline phosphatase levels. The peripheral blood of these patients showed segmented neutrophils, bands, and occasional metamyelocytes. When young cells such as myelocytes were seen, they did not persist. A high WBC with malignancy is a late phenomenon, usually occurring shortly before death, and does not correlate with any pathologic findings such as necrosis, white cell infiltration of the tumor, or specific inflammatory changes. most of the associated tumors are of giant cell size, but serum showed no evidence of colony stimulating activity. This was true of two tumors reported in the literature, yet the tumors could be shown in vitro to produce colony stimulating activity. The tumor probably does produce some type of granulocytopoietin, but methods for detecting it are presently limited.