Speaking to the patient is the key ...

I found this in the low rectum of an elderly lady undergoing a flexible sigmoidoscopy because of rectal bleeding. A quick check with the patient confirmed my suspicions.  
WHAT IS THE DIAGNOSIS?

■ Rectal prolapse

The patient would know about that!

■ Solitary rectal ulcer syndrome

A good guess and patient would know about constipation and straining but actually not the correct answer

■ Likely serrated polyp syndrome

Hmm, what question would you ask patient? FH of CRC perhaps?

■ Likely FAP

Findings of a rectal pouch in FAP? No, that's not it!

explanation

On first glance this looks like a circumferential serrated polyp in the rectum.  Of course, this would be somewhat odd and furthermore, unlikely that the patient would know anything about this. 

Actually, on direct questioning she did know about her prolapse!  Another common endoscopic finding is an erythematous and oedematous patch, close to the anal margin.