1. Professor Neil A Shepherd
Special polyp types
Professor Neil A Shepherd
Gloucester, UK
NHSBCSP Pathology Day,
London, November 21, 2007

2. Pathology and the NHSBCSP
a polyp is any lesion raised above the level of an epithelial surface
suddenly, with BCSP, there are lots more colonoscopies
all done by experts with dye-spray of small lesions and EMR
we might expect to see the occasional funny and we need to be alert

3. A classification of polyps of the colorectum
adenomas
hyperplastic polyps
mixed polyps
inflammatory polyps
juvenile polyps
Peutz-Jeghers polyps
stromal polyps
syndromic polyps – the triumvirate of polyposes, Cowden’s, Cronkhite-Canada, etc
Morson & Dawson, 2003

4. A classification of polyps of the colorectum
adenomas
hyperplastic polyps
mixed polyps
inflammatory polyps
juvenile polyps
Peutz-Jeghers polyps
stromal polyps
syndromic polyps – polyposes, Cowden’s, Cronkhite-Canada, etc
but some ‘polyps’ likely to be excised in BCSP are not in the list…..

5. 68M. Polypoid nodule in rectum.
chromogranin
synaptophysin

6. Gloucestershire BCSP, January-October 2007
normal 30
19.87%
cancer 24
15.89%
low risk polyps 20
13.25%
intermediate risk polyps 38
25.17%
high risk polyps 22
14.57%
abnormal result, not polyps 6
3.97%
refer for surgery (polyp) 5
3.31%
miscellaneous
TOTAL
151
100%

7. A classification of polyps of the colorectum
adenomas
hyperplastic polyps
mixed polyps
inflammatory polyps
juvenile polyps
Peutz-Jeghers polyps
stromal polyps
syndromic polyps – polyposes, Cowden’s, Cronkhite-Canada, etc
Morson & Dawson, 2003

8. Hyperplastic polyps about 25% of all polyps Issues:
differentiating them from mixed polyps & serrated adenoma
when they are large and right-sided and show SSP features
when they show epithelial misplacement – inverted hyperplastic polyps

9. Inverted hyperplastic polyps
closely related to right sided SSPs
Shepherd, 1991

10. A classification of polyps of the colorectum
adenomas
hyperplastic polyps
mixed polyps
inflammatory polyps
juvenile polyps
Peutz-Jeghers polyps
stromal polyps
syndromic polyps – polyposes, Cowden’s, Cronkhite-Canada, etc
Morson & Dawson, 2003

11. Inflammatory polyps the most common ‘other’ entity in BCSP
most are single/scanty and not related to CIBD (UC, CD, chronic infection such as schisto)
in the age group of the BSCP population, diverticulosis-associated polyps, polypoid mucosal prolapse, post-interventional polyps more common

12. 67F. BCSP. Diverticulosis and sigmoid colonic polyp.

13. Polypoid mucosal prolapse
in the BCSP age group, lower rectal/anal most common: inflammatory cloacogenic polyp
epithelial (villous) hyperplasia traps the unwary into calling them large villous adenomas
may be seen in association with diverticulosis, at stomas, in SUMPS, etc

14. Polypoid mucosal prolapse at the anorectal junction
a word of warning with inflammatory cloacogenic polyp
4 cases of adenomas of the lower rectum causing secondary polypoid mucosal prolapse
Parfitt & Shepherd, 2008

15. a b
Ki-67 c d
p53
Figure 1

16. a b
Ki-67 c d
p53
Figure 2

17. A classification of polyps of the colorectum
adenomas
hyperplastic polyps
mixed polyps
inflammatory polyps
juvenile polyps
Peutz-Jeghers polyps
stromal polyps
syndromic polyps – polyposes, Cowden’s, Cronkhite-Canada, etc
Morson & Dawson, 2003

18. Juvenile polyps commonest polyp in childhood
sporadic juvenile polyps do occur in adulthood but very rare in BCSP age group
inflammatory polyps can look similar
pretty unlikely to see juvenile polyposis….

19. Juvenile polyposis

20. ‘Atypical juvenile polyps’ with dysplasia

21. Juvenile polyposis
1 in 80,000
genetics becoming clearer but polymorphic: SMAD4 implicated in 25%
high rates of colorectal cancer: life time risk - ? up to 30%
dysplasia in atypical juvenile polyps
? surveillance ? prophylactic colectomy
Jass et al 1988,
Woodford-Richens et al, 2000

22. Quick quiz question
SMAD 4 mutation is implicated in about a quarter of cases of this condition. What does SMAD stand for? Is it:
somatic mutation in Arctic drosophila
serine-methionine-arginine deletion
small mothers against decapentaplegia

23. Quick quiz question
SMAD 4 mutation is implicated in about a quarter of cases of this condition. What does SMAD stand for? Is it:
somatic mutation in Arctic drosophila
serine-methionine-arginine deletion
small mothers against decapentaplegia

24. A classification of polyps of the colorectum
adenomas
hyperplastic polyps
mixed polyps
inflammatory polyps
juvenile polyps
Peutz-Jeghers polyps
stromal polyps
syndromic polyps – polyposes, Cowden’s, Cronkhite-Canada, etc
Morson & Dawson, 2003

25. Peutz-Jeghers polyposis

26. Peutz-Jeghers polyps syndrome about 1 in 100,000
sporadic PJ-like polyps described but very rare
? relationship to ‘inflammatory myoglandular polyp’
aren’t sporadic PJPs most likely to be post-inflammatory or post-mucosal prolapse?

27. Do sporadic Peutz-Jeghers polyps exist?
119 polyps in 38 patients
most patients with PJ-like polyps were actually shown to have PJS (scanty colonic polyps in the syndrome)
8 left: three small bowel ones with PJ features; 5 colonic with suggestive features of PJPs (top GI pathologists could not tell for certain: mucosal prolapse could not be excluded). 40% in BCSP screening age group
if they exist, sporadic colorectal PJ polyps are very rare
Burkhart et al. Do sporadic Peutz-Jeghers polyps exist? Experience from a large teaching hospital. AJSP, August 2007

28. A classification of polyps of the colorectum
adenomas
hyperplastic polyps
mixed polyps
inflammatory polyps
juvenile polyps
Peutz-Jeghers polyps
stromal polyps
syndromic polyps – polyposes, Cowden’s, Cronkhite-Canada, etc
Morson & Dawson, 2003

29. Stromal polyps GIST leiomyoma of muscularis mucosae
gastrointestinal schwannoma
neurofibroma
ganglioneuroma
epithelioid mucosal nerve sheath tumour
intestinal perineurioma
fibroblastic polyp
inflammatory fibroid polyp
that’s enough stromal polyps (Ed)

30. Small polypoid rectal nodules

31. Gastrointestinal schwannoma
33 cases: 4 oesophagus, 24 stomach, 2 colon and 3 rectum
mainly within muscularis propria and/or subserosa
none encapsulated but all well circumscribed
32/33 cuff of lymphocytes
only 12 originally called schwannoma
S100 and vimentin +ve
CD117, CD34, ASMA, desmin –ve
nestin 80% positive; GFAP 64% positive
all showed some nuclear pleomorphism: ? longevity: no mitoses
all benign
Hou et al, 2006 (Histopathology)

33. Colonic polypoid mucosal lesions with mucosal entrapment and epithelial serration
A feature only rarely seen in GISTs

34. Colorectal intramucosal tumours with epithelial ‘entrapment’
Name
First recognised
S100
CD 34
EMA
Epithelial serration
Clinical features
neuro-fibroma
The year dot
+ ve
-ve
- ve
occasionally
Most solitary NF
ganglio-neuroma
probably down to Carney…
+ve
not
described
sporadic
or NF-1, MEN 2b
benign fibroblastic polyp of colon
2004
3/13
none
intestinal
peri-neurioma
2005
5/9
epithelioid NS tumour
+/-ve
0/6

35. CD34 positive: ‘neural’ markers negative
Benign fibroblastic polyp of colon: Eslami-Varzaneh F, Washington K, Robert ME, Kashgarian M, Goldblum JR, Jain D. AJSP 2004; 28:
CD34 positive: ‘neural’ markers negative

36. EMA positive: CD 117, CD 34, S100 negative
Intestinal perineurioma: Hornick JL, Fletcher CDM. AJSP 2005; 29:
EMA positive: CD 117, CD 34, S100 negative

37. S100 & CD 34 positive: EMA & CD 117 negative
Mucosal epithelioid nerve sheath tumour: Lewin MR, Dilworth HP, Alfa AK, Epstein JI, Montgomery E. AJSP 2005; 29:
S 100
CD 34
S100 & CD 34 positive: EMA & CD 117 negative

38. Colorectal intramucosal tumours with epithelial ‘entrapment’ and surface serration
extraordinary ‘new’ descriptions of three entities – smallish spindle cell polypoid tumours with epithelial entrapment and surface epithelial serration
? recent recognition due to legislation to allow Medicare customers to undergo screening colonoscopy (2001)
lesions are mainly of schwann cell/perineural cell origin
differentiation by immunohistochemistry although specificity of these entities is a little doubtful..
Zamecnik & Chlumska, 2006
Groisman et al, 2006
all are benign and should not be confused with more sinister lesions such as GISTs and others

39. Take home messages: special polyp types
inflammatory polyp/polypoid mucosal prolapse most common after adenomas and HPs
remember other lesions can be polypoid – leiomyoma of mm and rectal carcinoid – clinical, endoscopic and imaging correlation important
the ‘hamartomatous’ polyps and syndromes are very rare (but not unheard of) in the BCSP age group
serrated change can be a secondary phenomenon (polypoid mucosal prolapse, fibroblastic polyps, etc)