Structural aspects of a placenta from a case of maternal acute lymphatic leukaemia.

After delivery of a healthy female child from a mother suffering from acute lymphatic leukaemia (35th week of gestation) the placenta was examined by light and electron microscopy. Morphologically, the villi in this placenta from a case of maternal acute lymphatic leukaemia differed from those in a normal placenta in the following respects: 1. The frequent occurrence of fibrinoid deposits on the free surface of the syncytiotrophoblast and the pronounced formation of syncytial cytoplasmic protrusions. 2. Dilatation of syncytial rough endoplasmic reticulum, numerous syncytial knots and numerous autophagosomes. 3. An excessive number of villous cytotrophoblastic cells. 4. Thickening of the trophoblastic basement membrane. 5. Bulbous endothelial cells with cytoplasm in fetal capillaries. 6. Strands of basement membrane-like material within the villous stroma. 7. Phagocytosis of nucleus-containing cells by the syncytiotrophoblast. 8. Cells with an abundant number of microtubular bundles within the villous stroma. It is suggested that phagocytosis of nucleus-containing cells (tumour cells?) by the syncytium could play a role in the prevention of transplacental metastasis.