Case 18 Answer

Notice the thickened endometrium with a large amount of vascularity within it. No IUP. Here is a picture from 2 days prior I believe showing a probable gestation sac low in the canal.

Answer: retained products of conception

It is not uncommon to have a thickened endometrial stripe post abortion (spontaneous or otherwise) but all that material should only be clot, ie non vascular. If you see blood blood extending into, or even within the material, worry about RPOC

reference: http://radiopaedia.org/articles/retained-products-of-conception

several people considered gestational trophoblastic disease (molar pregnancy). Generally those are much more cystic appearing with the so-called “snowstorm” appearance. ex: http://radiopaedia.org/articles/hydatidiform-mole