Two pregnancy-associated late relapses in acute lymphoblastic leukemia

Late relapses of acute lymphoblastic leukemia occurred in two women in associated with pregnancy, 7 and 17 years, respectively, after the initial diagnosis of leukemia. In both cases and in a similar pregnancy-associated case in the literature relapse was accompanied by the appearance of vacuolization in the leukemic lymphoblasts. In order to explain how late relapses can occur at all and how they may be triggered by endocrine events such as pregnancy, it seems necessary to assume that some leukemic cells are not autonomous and that they may preserve the faculty of normal homeostatic regulation.