A caecal polyp

This polyp was found in the caecum. 
WHAT'S THE LIKELY DIAGNOSIS?

■ Inverted appendix

The right shape but the wrong crypt pattern!

■ SSL

Absolutely, those crypts don't lie!

■ Adenomatous polyp

Wrong crypt pattern!

■ Likely underlying appendiceal tumour

Now, that's a wild guess!

explanation

I did hesitate for a moment as the lesion did, at first sight seem to arise from the caecal pole and was reminiscient of an inverted appendix (see below). However, on closer scrutiny, it has the typical wide-open crypts of a 'sessile serrated polyp' and wasn't actually that close the the caecal pole. It was removed without incidence after injecting some saline below.