Ultrastructural observation on a case of preleukemia transformed to hypogranular promyelocytic leukemia

An 80-year-old female with the variant type of M3 acute promyelocytic leukemia is described. The disease presented itself as a preleukemia of more than 3 years duration. The diagnosis was established only after examination of the cells with the transmission electron microscope. She responded favourably to subcutaneous injection of cytosine arabinoside. No signs of disseminated intravascular coagulation (DIC) were observed during the course of the disease.