Colorectal pathology

Question 1

What is a polyp?

Answer 1

Protrusion above an epithelial surface

Question 2

Types of polyps

Answer 2

Epithelial or mesenchymal

Question 3

Types of benign epithelial polyps

Answer 3

Neoplastic - adenoma, hamartomatous - juvenile polyp, Peutz-jeghers, metaplastic

Question 4

Types of malignant epithelial polyps

Answer 4

Polypoid (adenocarcinomas), carcinoid polyps

Question 5

Benign mesenchymal polyps

Answer 5

Lipoma, Lymphangioma, Haemangiomas, Fibromas, Leiomyoma

Question 6

Malignant mesenchymal polyps

Answer 6

Sarcoma, lymphotamous

Question 7

Why must all adenomas be removed?

Answer 7

They are dysplastic - pre-malignant

Question 8

Microscopic view of adenomas

Answer 8

Tubulovillous structures

Question 9

Which staging predicts prognosis in colorectal carcinoma?

Answer 9

Duke’s staging

Question 10

Dukes staging (A-C)

Answer 10

Dukes A - confined by muscularis propria
Dukes B - through muscularis propria
Dukes C - metastatic to lymph nodes

Question 11

Which side does colorectal carcinoma most commonly affect?

Answer 11

Left side (75%)

Question 12

Presenting complaint of colorectal carcinoma which affects the left side (rectum, sigmoid, descending colon)

Answer 12

Blood per rectum, altered bowel habit and obstruction

Question 13

Presenting complaint of colorectal carcinoma which affects the right side (caecum, ascending colon)

Answer 13

Anaemia or weight loss

Question 14

Patterns of spread of colorectal carcinoma

Answer 14

Local invasion, lymphatic spread, haematogenous

Question 15

Hereditary non polyposis coli:

• How many polyps?
• Autosomal dominant or recessive?
• Where is the defect?
• Which tumours does it cause?
• Which cancers is it related to?

Answer 15

• <100 polyps
• Autosomal dominant
• Defect in DNA mismatch repair, mutation in MLH-1, MSH-2, PMS-1 or MSH-6 genes
• Right sided tumours and mucocinos tumours
• Gastric and endometrial carcinoma

Question 16

Familial adenomatous polyposis:

• How many polyps?
• Autosomal dominant or recessive?
• Where is the defect?
• Which cancers is it related to?

Answer 16

• > 100 polyps
• Autosomal dominant
• Tumour suppressor defect, inherited mutation in FAP gene
• Desmoid tumours and thyroid carcinoma

Question 17

What is diverticular disease?

Answer 17

Mucosal herniation through the muscle coat

Question 18

Where does diverticular disease often occur?

Answer 18

Sigmoid colon

Question 19

What can diverticular disease be due to?

Answer 19

Low fibre intake

Question 20

Complications of diverticular disease

Answer 20

• Pericolic abscess
• Perforation
• Haemorrhage
• Fistula
• Stricture

Question 21

Diagnosis of diverticulosis

Answer 21

History and clinical examination, barium enema and sigmoidoscopy

Question 22

Clinical features of diverticulitis

Answer 22

Left iliac fossa pain/tenderness, the patient may be septic, and there may be altered bowel habit

Question 23

Which classification is used for diverticulitis

Answer 23

Hinchey classification

Question 24

Hinchey classification

Answer 24

• Stage 0 – clinically mild diverticulitis
• Stage Ia – confined pericolic diverticulitis (beside the colon)
• Stage Ib – abscess formation (<5cm) in the proximity of the primary inflammatory response
• Stage II – intra-abdominal abscess, pelvic or retroperitoneal abscess, abscess distant from the primary inflammatory process
• Stage III – generalised purulent peritonitis
• Stage IV – faecal peritonitis

Question 25

Treatment for uncomplicated diverticulitis

Answer 25

Antibiotics

Question 26

Treatment for complicated diverticulitis

Answer 26

Percutaneous drainage, Hartmann's procedure, laparoscopic lavage and drainage, primary resection/anastomosis

Question 27

Colitis

Answer 27

Inflammation of the colon

Question 28

Causes of colitis

Answer 28

- Infective colitis - Ulcerative colitis - Crohn’s disease - Ischaemic colitis

Question 29

Symptoms of colitis

Answer 29

Diarrhoea +/- blood, abdominal cramps, dehydration, sepsis, weight loss and anaemia

Question 30

Diagnosis of colitis

Answer 30

X-ray, sigmoidoscopy + biopsy, stool cultures, barium enema

Question 31

Treatment of ulcerative colitis/Crohn's colitis

Answer 31

IV fluids, IV steroids, GI rest

Question 32

In which patients is ischaemic colitis most common?

Answer 32

Elderly or arteriopaths

Question 33

Colonic angiodysplasia: - What is it? - Diagnosis - Management

Answer 33

- Small vascular malformation of the gut which can cause submucosal lakes of blood - Angiography, colonoscopy - Embolisation, endoscopic ablation, surgical resection

Question 34

Causes of large bowel obstruction

Answer 34

Colorectal cancer, benign stricture, volvulus

Question 35

Volvulus

Answer 35

When a loop of intestine twists round itself

Question 36

Treatment for large bowel obstruction

Answer 36

Resuscitate, operate, stenting

Question 37

Diagnosis of sigmoid volvulus

Answer 37

Plain x-ray abdomen, rectal contrast

Question 38

Treatment for sigmoid volvulus

Answer 38

Flatus tube, surgical resection

Question 39

Risk factors for colorectal cancer

Answer 39

- Older age - Low intake of fibre - High intake of fat, sugar, alcohol, red meat, processed meats - Obesity - Smoking - Lack of physical exercise

Question 40

Ways of presenting with colorectal cancer

Answer 40

Bowel screening programme, urgent - via surgical outpatient department or endoscopy, emergency (obstruction, rectal bleeding, palpable mass, perforation)

Question 41

Signs and symptoms of right sided cancers

Answer 41

- Unexplained iron deficiency anaemia - Persistent tiredness - A persistent and unexplained change in bowel habit - Unexplained weight loss - Abdominal pain (colicky) - Lump in the abdomen

Question 42

Signs and symptoms of cancers in the left side and rectum

Answer 42

- Rectal bleeding - Feeling of incomplete emptying - Worsening constipation

Question 43

Investigations for colorectal cancer

Answer 43

Sigmoidoscopy, colonoscopy, CT colonography

Question 44

Steps in transformation of polyp to cancer

Answer 44

Normal epithelium (via APC mutation and COX-2 overexpression) → Hyperproliferative epithelium. Aberrant cryptic foci → Small adenoma (via K-ras mutation) → Large adenoma (via p35 mutation and loss of 18q) → Colon carcinoma

Question 45

Surgery options for colorectal cancer

Answer 45

Right hemicolectomy, extended right hemicolectomy, transverse colectomy, sigmoid colectomy, anterior resection, APR

Question 46

Right hemicolectomy

Answer 46

Right colon removed and ileocolic anastomosis

Question 47

Extended right hemicolectomy

Answer 47

Right colon and part of transverse colon removed, anastomosis between parts of colon

Question 48

Transverse colectomy

Answer 48

Transverse colon removed and anastomosis between parts of colon

Question 49

Sigmoid colectomy

Answer 49

Part of sigmoid colon removed and anastomosis between parts of colon

Question 50

Anterior resection

Answer 50

Part of rectum removed, remaining parts anastomosed

Question 51

APR

Answer 51

Sigmoid colon divided, anus resected and perianal skin is closed, colonostomy

Question 52

Factors influencing enhanced recovery following surgery for colorectal cancer

Answer 52

No premed, no NGT, no bowel prep, avoid fluid overload, prevent hypothermia, no drains, small incision, early mobilisation, early removal of catheters, NSAIDs, no opiods

Question 53

Colorectal cancer treatment following surgery

Answer 53

Chemotherapy, radiotherapy depending on staging

Question 54

Palliation for colorectal cancer

Answer 54

Stenting, palliative chemotherapy/radiotherapy, defunctioning, bypass