Erythroleukaemic myelosis in benzene poisoning.

The work reported in this paper was an attempt to elucidate the pathology of a case of acute leukaemia in a workman engaged in an operation which exposed him to a notable inhalation of benzene vapour. Chronic intoxication with benzene is classically regarded as a cause of aplastic anamia, but the fact that atypical cases arise referable to the same cause has made it necessary to extend the toxicological picture of benzene poisoning and to include in it other forms which differ widely from the example given. Penati and Vigliani (1938) in a study presented at the Eighth International Congress for Industrial Accidents and Occupational Disease at Frankfurt reviewed all the toxicological literature up to that time, and divided the blood findings which appear in workers exposed chronically to the action of benzene into four groups: (l) Cases clinically, hamatologically, and pathologically typical of aplastic anamia; (2) cases clinically typical of aplastic anaemia, but showing active hamopoiesis, especially in the bone marrow, with numerous undifferentiated cells (pseudo-aplastic anamia); (3) atypical cases of aplastic anaemia with pathological evidence of myeloid hyperplasia or metaplasia resembling leukaemia especially in the spleen and in the liver; and (4) cases of indubitable chronic or acute leukaemia not infrequently of a leukamic type. These varieties of myelopathy, of which the leukamia-like hyperplastic pictures have been experimentally reproduced in several species of animal by means of suitable administration of benzene (Lignac, 1928, 1930, 1932, 1933 ; Hess, 1935), lead us to attribute to this compound not only the appearance of abnormal blood-cells characterized by regressive changes, but also a hyperplastic action on the hamopoietic organs which, in constitutionally predisposed subjects, may lead to the development of true leukamia. Cases have been described in the literature which present both clinically and pathologically the various aspects of leukeemia: chronic myeloid and lymphatic leukaemia, acute leukaemia, and acute leucopenic-