Another scary looking sigmoid polyp
This scary looking polyp was found in the sigmoid in a patient on a polyp surveillance programme.
WHAT IS THE LIKELY DIAGNOSIS?
a) Mucosal prolapse
Yes! You can't see any typical gland openings at the tip of this polyp. It's a mucosal prolapse polyp with a serrated lesion at the tip.
b) Adenomatous polyp
It's a battered polyp but without any recognisable crypt openings at the tip and therefore NOT adenomatous.
c) Malignant polyp
Well it looks scary and without an organised crypt pattern. All hallmarks of a malignant polyp. However, this lacks crypts because it's an innocent mucosal prolapse polyp!
You've seen a few examples now of the 'mucosal prolapsing conditions' which include solitary rectal ulcer syndrome and inflammatory cloacogenic polyps. First described in 1985 [GIE 1985;31:196–9] they are usually said to be rare. However, experienced endoscopists know that these are common in the sigmoid. I've never seen a mucosal prolapse polyp outside of the sigmoid and would actually not make this diagnosis elsewhere in the colon.
Histology is usually said to be the way to "confirm the diagnosis and rule out cancer". However, for me it's an endoscopic diagnosis. But I do understand that these lesions do look alarming. For this reason, I sometimes take it upon myself to resect the tip of the lesion, proving to all those of little faith, that the lesion is absolutely innocent.
However, I'm not sure that my surgical colleauges are always reassured by the histology which usually rambles on about 'distorted elongated branched crypts, with fibromuscular obliteration of lamina propria with lots of intramucosal haemorrhages and a splayed and hypertrophied muscularis mucosae". However, the bottom line of that pathology report will read; 'No dysplasia'.
This lesion, situated in a very spastic sigmoid, has been referred for resection.
WHAT IS THE LIKELY DIAGNOSIS?
a) lesion is not neoplastic
Yes, hard to believe but true!
b) lesion is adenomatous
Lesion is 'battered' but crypts don't look typically adenomatous
c) lesion is malignant
No way, lesion isn't angry red, chunky or devoid of crypts!
I couldn't stop myself! After yesterday's case of a rectal 'prolapse polyp, part of the 'Mucosal Prolapse Syndrome', I had to show an example of a sigmoid mucosal 'traction polyp' (my nomenclature). The mucosa at the apex of this sigmoid fold is traumatised and inflamed but not actually adenomatous! Histologically these lesions also appear somewhat bashed up. This is where pathologists may see 'pseudo-invasion' which is actually movement of crypts due to trauma and inflammation.
The sigmoid colon is the most 'powerful' part of the colon developing the force needed to go to the toilet. Presumably this is the reason that diverticular disease first develop in the sigmoid. The force can also create these pseudo-polyps from patches of inflammation which I presume gets tugged along with each peristaltic wave. The end result is that this is the most difficult part of the colon to make head an tail of polyps.
These are common lesions and if you are a 'therapeutic endoscopist', you will be refer these lesions. In these cases, I don't go overboard by placing a snare far down the 'pseudo-stalk'. If you did, you will find that it's taking a long time to cut through all that healthy sigmoid mucosal fold and you run the risk of a perforation (early or late).
Instead, I just catch the tip of the fold and ask my assistant to close the snare as quickly as possible. Of course, you don't need to worry about a type of chunky central vessel which you may find in an adenomatous polyp. Analysis of a small piece of mucosal apex confirmed a normal mucosa. Hopefully this was enough for everyone to relax ...