A 29-year-old woman with right chest pain was admitted for radiographic inv
estigation and found to have a round mass in the right lower zone. This was
initially suspected to be a hydatid lung cyst but was confirmed as a cysti
c mass by computed tomography and duly excised. Histologic examination reve
aled an amniotic fluid embolism. The patient had had a stillbirth three mon
ths earlier.