Colonic polyps

Question 1

Define Polyp?

Answer 1

• Excrescence of the mucosa
• Non-pathological
• Can be identifed by:
  
  • Sigmoidoscopy (flex/rigid)
  • Colonscopy
  • CT colonography

Question 2

Describe Inflammatory pseudopolyps?

Answer 2

• Regenerating islands of mucosa
• In ulcerative colitis

Question 3

Describe Hyperplastic polyps?

Answer 3

• <5 mm, increase in numbers with age
• Piling of goblet cells and absorptive cells
• Lined by columnar epithelium
• No malignant potential

Question 4

Describe Hamartomatous polyps?

Answer 4

• Tumour-like growths composed of tissues present at site where they develop
• Sporadic or part of familial syndromes
• Juvenile polyp: solitary hamartoma in children
  
  • ‘Cherry on stalk’

Question 5

Describe Neoplastic polyps?

Answer 5

• Tubular or villous adenomas
• Usually asymptomatic
• May cause blood/mucus on PR and tenesmus

Question 6

Name some hamartomatous polyposis syndromes?

Answer 6

• Juvenile polyposis
• Cowden syndrome

Question 7

Describe Juvenile polyposis?

Answer 7

• Autosomal dominant
• Hamartomatous polyps
• Increased colorectal cancer risk
  
  • Requires surveillance and polypectomy

Question 8

Descrbe Cowden syndrome?

Answer 8

• Autosomal dominant
• Macrocephaly + skin stigmata
• Intestinal hamartomas
• Increased risk of extra-intestinal cancer

Question 9

Name some important familial colorectal cancer syndromes?

Answer 9

• Familial adenomatous polyposis (FAP)
• Hereditary non-polyposis colorectal cancer (HNPCC)
• Peutz-Jeghers Syndrome

Question 10

Describe FAP?

Answer 10

• Autosomal dominant
• APC gene mutation on 5q22.2
• Gardner’s syndrome is a subgroup

Question 12

Describe the presentation of FAP?

Answer 12

• 1000s of polyps by 16yrs old
  
  • Mainly large bowel
  • Also stomach and duodenum
• Many will ultimately develop carcinoma
• May also be associated with CHPRE
  
  • Congenital hypertrophy of the retinal pigment epithelium

Question 13

Describe the abnormality here?

Answer 13

• CHPRE
  
  • Can occur in FAP

Question 14

Name some variants of FAP?

Answer 14

• Attenuated FAP
  
  • <100 adenomas, colorectal cancer develops later than FAP
• Gardener’s syndrome (TODE)
  
  • Thyroid tumours
  • Osteomas of mandible, skull and long bones
  • Dental abdnormalities
  • Epidermal cysts

Question 15

Describe the diagnosis and management of FAP?

Answer 15

• Diagnosis
  
  • Sigmoidoscopy and biopsy
  • Referral to genetics service
• Prophylactic colectomy

Question 16

Describe HNPCC?

Answer 16

• Autosomal dominant
• Mutation of mismatch reapir enzymes
  
  • MSH2 or ch 2p
• Most common cause of hereditary colorectal cancer

Question 17

Describe the presentation of HNPCC?

Answer 17

• Lynch 1: right sided CRC
• Lynch 2: CRC + gastric, endometrial, prostate, breast

Question 18

How can HNPCC be diagnosed?

Answer 18

• 3 2 1 rule
  
  • >3 family members over 2 generations with one <50 years old

Question 19

Describe Peutz-Jeghers Syndrome?

Answer 19

• Autosomal dominant
• STK11 mutation

Question 20

Describe the presentation of Peutz-Jeghers Syndrome?

Answer 20

• 10-15yrs old
• Mucocutaneous hyperpigmentation
  
  • Macules on palms and buccal mucosa
• Multiple GI hamartomatous polyps
  
  • Intussusception
  • Haemorrhage
• Increased cancer risk
  
  • CRC, pancreas, breast, lung, ovaries, uterus

Question 21

What are the classifications of neoplastic epithelial polyops?

Answer 21

• Tubular
• Tubulovillous
• Villous adenomas