A rare case of amniotic fluid embolism with massive platelet aggregations in pulmonary capillaries.

A 30-year-old woman at 37 weeks of gestation died during labor induction with oxytocin shortly after an episode of abrupt drop of fetal heart rate. Autopsy showed extensive microvascular plugging of the pulmonary capillaries by massive platelet aggregations. Aside from platelet aggregations, the keratinized substances and granulocytes were also shown in the capillary of pulmonary arterioles. These findings were not observed in other systemic organs (heart, liver, spleen, kidney, adrenal, alimentary canal and pancreas). In general, the postmortem histological diagnosis of amniotic fluid embolism consisted of demonstrating mucus, leukocytes, squamous, amorphous, and fatty cells in the arteries of the lung. To our knowledge, there have not been any reports regarding massive platelet aggregations shown at pulmonary capillaries in case of acute amniotic fluid embolism except for an experimental model. This is a rare case of amniotic fluid embolism in which massive platelet aggregations were confirmed in pulmonary capillaries by autopsy.