The pathologist and the hydropic placenta, fetus, or infant.

Many anatomic and histologic abnormalities, in large variety, are associated with fetal and placental edema. It is the pathologist's responsibility first, to identify these abnormalities, and second, to propose or to establish a mechanism by which a candidate abnormality might have led to development of edema. The first process, of documentation, is often assisted by antenatal studies that have identified a candidate lesion. However, the pathologist must bear in mind that the presence of one disorder does not exclude others. The second process, of elucidating the abnormal physiologic mechanisms by which edema developed, can prove elusive and may verge on investigative rather than diagnostic work. An outline for pathologic examination of the hydropic placenta or fetus is presented.