This 27 year-old G₁P₀ patient was seen at 30 weeks for abnormal views of the heart. The great vessels are not shown but were normal. No family history, and normal amniocentesis. The following images were obtained.

The clear finding is that of a large pericardial effusion (not pleural effusion since it does not dissect around the lungs), and a mass next to the base of the heart (look at image 1-2 and 7 in particular) Note also that the effusion demonstrates color Doppler signal, not because this is a vascular structure but because of the paradoxymal motion of the fluid sloshing in the pericardium. These combined findings are all typical of pericardial teratoma. (see also Intrapericardial teratoma )