Practical Gastrointestinal Endoscopy

THERAPEUTIC COLONOSCOPY 191
the snare removal of large numbers of non-neoplastic polyps
(Peutz–Jeghers syndrome, juvenile or inflammatory polyposis).
On first presentation of some such patients, as many as 60–100
such polyps may need removal, although their histology is of secondary
interest since there is little or no malignant potential. The
multiple snared polyps are first retrieved to the descending or
sigmoid colon, the colonoscope is then passed to the splenic flexure
and 500·mL of warm tapwater is syringe-injected through the
instrument channel. The proximal colon is air-insufflated until
the patient feels some distension and, just before the colonoscope
is withdrawn from the anus, a disposable or phosphate enema
can be injected through the endoscope. This ensures evacuation
and passage of most of the polyps or polyp fragments into a commode
within a few minutes.
Inflammatory polyps of 1·cm or larger should be removed since
sporadic adenomas can occur in colitis patients. Most postinflammatory
polyps, sometimes called pseudo-polyps, appear
as small shiny worm-like tags of healthy and non-neoplastic
tissue after the healing of previous severe colitis of any kind.
They can be ignored or, if in doubt, a few biopsies can be taken
to confirm their trivial nature. Larger postinflammatory polyps
have a tendency to bleed and there may be difficulty in distinguishing
them from adenomas since they can be composed of
granulation tissue or disorganized tissue remarkably similar to
that of a hamartomatous (juvenile) polyp. These larger polyps
can bleed surprisingly after snaring, partly because they tend to
have soft bases that ‘cheese-wire’ through too quickly compared
with the more muscular pedicle of other polyps, but also because
they may be very vascular. Any broad-based or sessile polyp,
and especially any raised plaque occurring after longstanding
ulcerative or Crohn’s colitis must be treated with suspicion, since
it may represent a so-called ‘DALM’ (dysplasia-associated lesion
or mass), the most visible part of a ‘field change’ of high-grade
dysplasia. With such dubious lesions, take mucosal biopsies
around the base before snaring to discount this possibility.
Malignant polyps
Malignancy is suspected if a polyp is irregular, ulcerated, firm to
palpation or thick-stalked. Firmness to palpation with the snare
tube is probably the best single discriminant. If malignancy is
possible, it is important to be certain that transection has been
made low down the stalk (to allow the pathologist a proper
assessment) and to ensure that any invasion within the stalk has
been removed, although without risking perforation. The endoscopist
should report, on the basis of multiple vertical cross-sections,
whether or not the polyp has been completely removed. If
necessary an early repeat examination can be made, preferably
within two weeks while there is visible healing ulceration to