Congenital leukemia with placental involvement. Report of a case with ultrastructural study.

The study of a stillborn infant and the placenta, showing extensive infiltration of fetal organs and chorionic villi by leukemic cells, is reported. The nature of the malignant cells was not apparent by light microscopic examination. Ultrastructural examination showed that these were immature myeloblasts, stressing the usefulness of electron microscopic study in establishing the diagnosis. The current case study seems to be the first in the literature in which both placenta and fetus were studied in extenso.