Case 21 Answer

Answer: Omental infarct

it is a bit of an unsual location (most are along the omental border of the right colon, but following surgery it can occur anywhere.

short write up: http://radiopaedia.org/articles/omental-infarction

nice Radiographics article: http://pubs.rsna.org/doi/pdf/10.1148/rg.317115046