08-02-23 - Gastrointestinal tumours (lower tract)

Question 1

Learning outcomes

Answer 1

• Describe common tumours of the small intestine
• Describe common tumours of the colon

Question 2

What % of GI tumours are tumours of the small intestine?

What are the 2 types of benign tumours of the small intestine?

What are the 3 types of mesenchymal tumour of the small intestine?

What % of benign small intestine tumours are adenomas?

Answer 2

• Only 3-6% of all GI tumours are in the small intestine
• 2 types of benign tumours of the small intestine:

1) Adenoma (25% of benign small intestine tumours)

2) Mesenchymal tumours
* Leiomyoma
* Lipoma
* Angioma

Question 3

What are the 2 types of malignant tumours of the small intestine?

Answer 3

• 2 types of malignant tumours of the small intestine:

1) Adenocarcinoma & Carcinoid

2) Lymphoma and Sarcomas

Question 4

What are the 2 types of benign tumour of the colon and rectum?

Which have the potential to be malignant?

Answer 4

• 2 types of benign tumour of the colon and rectum:

1) Non-neoplastic (no malignant potential)

2) Neoplastic -Adenoma (malignant potential)

Question 5

What are the 5 types of malignant tumour of the colon and rectum?

What % of malignant colon and rectum tumours are adenocarcinomas?

Answer 5

• 5 types of malignant tumour of the colon and rectum:

1) Adenocarcinoma (98% of malignant colon and rectum tumours)
* Adenocarcinoma is the most common type of colorectal cancer
* Colonic cancer = adenocarcinoma
* Means tumour that originates from the epithelial cells of the glands

2) Carcinoid

3) Anal zone carcinoma

4) Lymphoma

5) Leiomyosarcomas

Question 6

Small Intestine Benign Tumours – adenoma.

What ages do adenomas of the small intestine commonly appear?

What structure do they usually affect?

What can adenomas develop into?

Answer 6

• Small Intestine Benign Tumours – adenoma
• Adenomas of the small intestine commonly appear in 30- to 60-year-old patient with occult blood loss.
• They usually affect the ampulla of Vater, causing it to be enlarged and exhibit a velvety surface
• Adenomas have malignant potential, and can develop into adenocarcinomas

Question 7

Small Intestine Malignant Tumours – Adenocarcinoma.

Where do adenocarcinomas of the small intestine typically occur?

What age group do they typically affect?

What features do they usually present with? What is a polypoid lesion?

Answer 7

• Small Intestine Malignant Tumours – Adenocarcinoma
• Adenocarcinomas of the small intestine typically occur in the duodenum
• They usually occur in 40- to 70-year-old patients
• Adenocarcinomas of the small intestine present with a napkin-ringencircling pattern and polypoid exophytic masses
• Any discrete lesion protruding into the lumen of gastrointestinal (GI) tract appeared at endoscopy is called as “polypoid lesion”

Question 8

Small Intestine Malignant Tumours – Adenocarcinoma.

What can adenocarcinomas cause in the small intestine?

What are 5 symptoms of adenocarcinoma of the small intestine?

What is the five-year survival rate for adenocarcinomas of the small intestine?

Answer 8

• Small Intestine Malignant Tumours – Adenocarcinoma
• Adenocarcinomas in the small intestine can cause intestinal obstruction
• 5 symptoms of adenocarcinoma of the small intestine:

1) Cramping pain

2) Nausea

3) Vomiting

4) Weight loss

5) May cause obstructive jaundice
* The pancreatic duct or ampulla of vater can completely close
* Bile won’t be able to move into the duodenum, causing obstructive jaundice

• The five-year survival rate for adenocarcinomas of the small intestine is 70%, as it is very easily detected

Question 9

Benign tumours of the colon and rectum

What are the 2 types of benign tumours of the colon and rectum?

What are the 2 types of Non-neoplastic polyps?

What are the 3 types of Neoplastic polyps (adenomas)?

What are characteristics of each type?

Answer 9

• Benign tumours of the colon and rectum
• 2 types of benign tumours of the colon and rectum:

1) Non-neoplastic polyps (won’t become malignant)
* Hyperplastic (90%) – sessile (lying flat on surface)
* Hamartomatous

2) Neoplastic polyps (adenomas - has malignant potential)
* Tubular – pedunculated (have a little stalk like a mushroom)
* Villous – sessile (flat on surface)
* Tubulovillous – mix between the two

Question 10

Hyperplastic Polyps.

What are size of Hyperplastic Polyps?

What age do they affect?

What are characteristics of hyperplastic polyps?

Where are hyperplastic polyps found half of the time?

Can hyperplastic polyps become malignant?

What are 3 histological features of Hyperplastic Polyps?

Answer 10

• Hyperplastic Polyps are <5 mm
• They typically affect patients >age 60
• Hyperplastic polyps are characterised as nipple-like, hemispheric, smooth, moist protrusions of the mucosa
• 1/2 of hyperplastic polyps are found in the rectosigmoid colon
• Hyperplastic polyps have no malignant potential
• 3 histological features of Hyperplastic Polyps:

1) Well-formed glands and crypts

2) Lined by non-neoplastic epithelial cells

3) Most of which show differentiation into mature goblet or absorptive cells

Question 11

What are 2 types of Hamartomatous Polyps?

Answer 11

• 2 types of Hamartomatous Polyps:

1) Juvenile polyps

2) Peutz-Jeghers polyps

Question 12

What type of structure are Juvenile polyps?

What age do they affect?

Where do they typically occur?

What are 3 histological features of juvenile polyps?

Can juvenile polyps become malignant?

Answer 12

• Juvenile polyps are malformations of the mucosal epithelium and lamina propria
• Juvenile polyps affect children <5 years old
• 80% of juvenile polyps occur in the rectum
• 3 histological features of juvenile polyps:

1) Abundant cystically dilated glands

2) Inflammation is common

3) Surface may be congested or ulcerated

• Juvenile polyps have no malignant potential

Question 13

What causes Peutz-Jeghers syndrome?

Where can Peutz-Jeghers polyps be located?

What 3 structures do Peutz-Jeghers polyps involve?

What is their structure like?

Do Peutz-Jeghers polyps have malignant potential?

What 5 carcinomas does Peutz-Jeghers syndrome increase the risk of?

Answer 13

• Peutz-Jeghers syndrome is an autosomal dominant syndrome caused by a mutation of the gene STK11 (LKB1) located on chromosome 19
• Peutz-Jeghers polyps can be located in the stomach 25%; colon 30%; and small bowel
• 3 structures Peutz-Jeghers polyps involve:
  1) Mucosal epithelium,
  2) Lamina propria, and muscularis
  3) Mucosa
• Peutz-Jeghers polyps Tend to be large and pedunculated (mushroom stalk)
• Peutz-Jeghers polyps do not have malignant potential
• 5 carcinomas Peutz-Jeghers syndrome increases the risk of:
  1) Pancreas
  2) Breast
  3) Lung
  4) Ovary
  5) Uterus
   

Question 14

What are neoplastic polyps also known as?

What kind of lesions are they?

How can they differ in appearance?

What % occur in different age groups?

How common are they in males and females?

What do adenomas arise as a result of?

What are the 3 ways adenomas can be classified?

What % of cases does each type make up?

Answer 14

• Neoplastic polyps are also known as adenomas
• They are intraepithelial lesions
• They can be small penduculated lesions to large neoplasms that are usually sessile
• 20% to 30% before age 40, rising to 40% to 50% after age 60
• As common in male as females
• Adenomas arise as the result of epithelial proliferative dysplasia (abnormal cells in tissue)
• 3 ways adenomas can be classified:

1) Tubular adenomas
* Most common 75%
* Small, pedunculated lesions (mushroom stalk appearance)

2) Villous adenomas
* 1-10%
* Large neoplasms that are usually sessile (flat)
* Neoplasms are an abnormal mass of tissue that forms when cells grow and divide more than they should or do not die when they should

3) Tubulovillous adenoma
* 5-15%

Question 15

What are adenomas a precursor for?

What 3 factors is risk of adenomas becoming colorectal adenocarcinomas associated with?

What is it impossible to do from just inspecting polyps?

Answer 15

• Adenomas are a precursor lesion for invasive colorectal adenocarcinomas
• 3 factors risk of adenomas becoming colorectal adenocarcinomas associated with:

1) Polyp size
* Rare in tubular adenomas < 1 cm
* High risk (40%) in sessile villous adenomas > 4 cm

2) Histological architecture

3) Severity of epithelial dysplasia
* Severe dysplasia (abnormal cells) , when present, is often found in villous areas

• It is Impossible from gross inspection of a polyp to determine its clinical significance

Question 16

Where do tubular adenomas normally located?

What size are they?

How do the large and small tubular adenomas differ in structure?

Answer 16

• 90% of tubular adenomas occur in the colon (can also occur in stomach and small intestine)
• They are Usually < 2.5 cm
• Small tubular adenomas are smooth-contoured and sessile
• Larger ones tend to be coarsely lobulated and have slender stalks raspberry - like

Question 17

What are 5 features in the morphology of tubular adenomas?

Answer 17

• 5 features in the morphology of tubular adenomas:

1) Stalk is composed of fibromuscular tissue and prominent blood vessels –

2) Presence of dysplastic epithelium, which lines glands as a tall, hyperchromatic, disordered epithelium that may show mucin vacuoles

3) Degree of dysplasia is lowgrade (degree of abnormal cells)

4) High-grade dysplasia may be present

5) Carcinomatous invasion into the submucosal stalk of the polyp constitutes invasive adenocarcinoma

Question 18

What groups do Villous Adenomas typically affect?

Where do they occur in the body?

Are they flat or protruding?

How long are they?

How do they present?

Answer 18

• Villous adenomas typically affect older persons
• They are commonly in the rectum and rectosigmoid colon
• Villous adenomas are sessile (flat), up to 10 cm
• They are velvety or cauliflower like masses projecting 1 to 3 cm above the surrounding normal mucosa

Question 19

What are 4 features in the histology of villous adenomas?

What is carcinoma in situ?

Answer 19

• 4 features in the histology of villous adenomas:

1) Finger-like villiform extensions of the mucosa

2) Covered by dysplastic, sometimes very disorderly columnar epithelium

3) All degrees of dysplasia may be encountered

4) When invasive carcinoma occurs (40%), there is no stalk as a buffer zone, and invasion is directly into the wall of the colon

• Carcinoma in situ us when cells breach the basal membrane and go into the stroma
   

Question 20

Which colorectal adenomas are symptomatic and asymptomatic?

How are they often discovered?

What invasion is regarded as having little or no metastatic potential?

Answer 20

• Colorectal tubular and tubulovillous adenomas may be asymptomatic, and many are discovered during evaluation of anaemia or occult bleeding
• Villous adenomas are more symptomatic, and often discovered because of overt rectal bleeding
• Intramucosal carcinoma with lamina propria invasion only is regarded also as having little or no metastatic potential

Question 21

What 3 criteria have to be met for Endoscopic removal of a pedunculated adenoma to be regarded as adequate?

When can invasive adenocarcinoma not be adequately resected by polypectomy?

Answer 21

• 3 criteria have to be met for Endoscopic removal of a pedunculated adenoma to be regarded as adequate:

1) The adenocarcinoma is superficial and does not approach the margin of excision across the base of the stalk

2) There is no vascular or lymphatic invasion

3) The carcinoma is not poorly differentiated

• Invasive adenocarcinoma arising in a sessile polyp cannot be adequately resected by polypectomy – further surgery may be required

Question 22

What is Familial Adenomatous Polyposis (FAP) Syndrome?

What mutation causes FAP syndrome?

What do patients with FAP syndrome develop?

What are these structures like histologically?

What is the risk of developing adenocarcinoma in a patient with FAP syndrome?

Answer 22

• Familial Adenomatous Polyposis (FAP) Syndrome is a special type of adenocarcinoma
• FAP syndrome is cause by Mutations of the adenomatous polyposis coli (APC) gene on chromosome 5q21-22
• Patients typically develop 500 to 2500 colonic polyps that carpet the mucosal surface
• Histologically, the vast majority of polyps are tubular adenomas
• 100% risk of developing adenocarcinoma before age 30 = total colectomy indicated

Question 23

Colorectal Carcinoma.

What % of cancers of the large intestine are adenocarcinomas?

At what age is the peak incidence?

How does location of adenocarcinoma affect the incidence in different genders?

Where are the highest death rates?

Answer 23

• Colorectal Carcinoma
• 98% of all cancers in the large intestine are Adenocarcinomas
• Peak incidence is between ages 60 and 79
• In the rectum, the male to female ratio for adenocarcinomas in the large intestine is 1.2 :1
• For more proximal tumours, the male to female ratio is equal
• Highest death rates in the US, Australia, New Zealand, and Eastern European countries

Question 24

What are 5 dietary factors that contribute to colorectal tumours?

Answer 24

• 5 dietary factors that contribute to colorectal cancer:
  1) Excess dietary caloric intake relative to requirements
  2) Low content of vegetable fibre
  3) High content of refined carbohydrates
  4) Intake of red meat
  5) Decreased intake of protective micronutrients

Question 25

Pathogenesis flow chart for colorectal carcinomas (in picture)

Answer 25

Question 26

What are 5 different sites for colorectal tumours?

What % of total cases occur at each one?

Answer 26

• 5 different sites for colorectal carcinomas:
  1) Rectosigmoid colon, 55% of cases
  2) Caecum / Ascending colon, 22%
  3) Transverse colon, 11%
  4) Descending colon, 6%
  5) Other sites, 6%

Question 27

How do tumours in the proximal colon present?

What tends to be common with these tumours?

What can tumours in the proximal colon penetrate?

Answer 27

• Tumours in the proximal colon present as polypoid, exophytic masses
• Obstruction is common with these tumours
• Tumours in the proximal colon can penetrate the bowel wall as subserosal and serosal white, firm masses

Question 28

How do tumours in the distal colon present?

What are their margins like?

How does it affect the lumen of the bowel?

How do they penetrate the bowel wall?

How might the patient present?

Answer 28

• Tumours in the distal colon present as annular, encircling napkin-ring constrictions
• The margins are classically heaped up, beaded, and firm, and the mid-region is ulcerated
• The lumen is markedly narrowed, and the proximal bowel may be distended
• Tumours of the distal colon can penetrate the bowel wall as subserosal and serosal white, firm masses
• The patient can often present with alternation between diarrhoea and constipation

Question 29

Barium enema technique for colon tumour X-ray

Answer 29

Question 30

What are 4 histological features of colorectal tumours?

Answer 30

• 4 histological features of colorectal carcinomas:

1) May range from tall, columnar cells resembling their counterparts in adenomatouslesions to

2) Undifferentiated, frankly anaplasticmasses

3) Many producemucin

4) Invasive tumour incites a strong desmoplastic stromal response

Question 31

What are potential symptoms of colorectal tumours?

What are 3 symptoms of Caecum and right colonic tumours?

What are 3 symptoms of left-sided tumours?

What does iron-deficiency anaemia in an older male mean?

What can signify more extensive disease?

Answer 31

• Colorectal tumours can be asymptomatic for years
• 3 symptoms of Caecum and right colonic tumours:
  1) Fatigue
  2) Weakness
  3) Iron-deficiency anaemia
• 3 symptoms of left-sided colorectal tumours:
  1) Occult bleeding (blood in faeces that isn’t visibly apparent)
  2) Changes in bowel habit
  3) Crampy left lower quadrant discomfort
• Iron-deficiency anaemia in an older male means means gastrointestinal cancer until proven otherwise
• Systemic manifestations such as weakness, malaise, and weight loss signify more extensive disease

Question 32

What are 2 ways colorectal tumours can spread?

Answer 32

• 2 ways colorectal tumours can spread:

1) Direct extension into adjacent structures

2) Metastasis through Lymphatics and Blood vessels
* Regional lymph nodes, liver, lungs, and bones, serosal membrane of the peritoneal cavity, brain, and others

Question 33

What is Duke’s Stage classification used for?

What are the 3 Duke Stages?

What us the survival rate at each stage?

Answer 33

• Duke’s Stage classification is used for grouping adenocarcinomas.
• The 3 Duke Stages:

A) Confined to the submucosa or muscle layer (90+% survival rate)

B) Spread through the muscle layer, but does not yet involve the lymph nodes (70%)

C) Involving lymph nodes (35%)

Question 34

What are carcinoid tumours derived from?

What % of colorectal malignancies and small intestinal malignant tumours do they make up?

What age are they commonly seen in?

What are histological differences between benign and malignant carcinoid tumours?

What 4 things does aggressive behaviours of carcinoid tumours correlate with?

Answer 34

• Carcinoid tumours are derived from endocrine cells
• Carcinoid tumours make up 2% of colorectal malignancies but almost 1/2 of small intestinal malignant tumours
• Commonly seen in age >60
• No reliable histological difference between seemingly benign and obviously malignant carcinoid tumours
• 4 things does aggressive behavious of carcinoid tumours correlate with:
  1) Site of origin
  2) Depth of local penetration
  3) Size of the tumour
  4) Histological features of necrosis and mitosis

Question 35

Carcinoid Tumours Morphology. How do carcinoid tumours usually present?

What is the most common site for carcinoid tumours?

What 4 other structures can carcinoid tumours also appear in?

How do carcinoid tumours appear on transection?

Answer 35

• Carcinoid Tumours Morphology
• Carcinoid tumours usually present as solitary lesion except ileum and stomach (multicentric)
• They present as intramural or submucosal masses that create small polypoid or plateau-like elevations < 3 cm.
• Appendix is the most common site for carcinoid tumours
• 4 other structures can carcinoid tumours also appear in:
  1) Small intestine (primarily ileum)
  2) Rectum
  3) Stomach
  4) Colon
• Carcinoid tumours have a solid, yellow-tan appearance on transection

Question 36

Carcinoid Tumours Histology.

What might neoplastic cells form?

How do tumour cells present?

What do electron microscopy tumour cells contain?

Answer 36

• Carcinoid Tumours Histology
• Neoplastic cells may form discrete islands, trabeculae, stands, glands, or undifferentiated sheets
• Tumour cells are monotonously similar, having a scant, pink granular cytoplasm and a round to oval stippled nucleus
• Electron microscopy tumour cells contain membrane-bound secretory granules with dense-core granules in the cytoplasm

Question 37

Carcinoid Tumours - Clinical Features.

What symptoms do carcinoid tumours rarely produce?

How are local symptoms caused?

What can some neoplasms be associated with?

What is carcinoid syndrome due to?

What are 9 symptoms of carcinoid syndrome?

Answer 37

• Carcinoid Tumours - Clinical Features
• Carcinoid tumours rarely produce local symptoms
• Local symptoms are caused by angulation or obstruction of the small intestine
• Some neoplasms are associated with a distinctive carcinoid syndrome
• Carcinoid syndrome is from excess of serotonin (5-hydroxytryptamine), 5-HT
• 9 symptoms of carcinoid syndrome:
  1) Cutaneous flushes
  2) Apparent cyanosis
  3) Diarrhoea
  4) Cramps
  5) Nausea
  6) Vomiting
  7) Cough
  8) Wheezing
  9) Dyspnoea

Question 38

Carcinoid Tumours - Clinical Features.

Which carcinoids do not metastasize?

Which carcinoid tumours often spread to the lymph nodes?

What is the overall five-year survival rate for carcinoids?

Answer 38

• Carcinoid Tumours - Clinical Features
• Appendiceal and rectal carcinoids do not metastasize
• 90% of ileal, gastric, and colonic carcinoids that have penetrated halfway through the muscle wall have spread to lymph nodes and distant sites such as the liver at the time of daignosis
• The overall five-year survival rate for carcinoids is 90%

Question 39

What is the definition of primary gastrointestinal lymphoma?

Answer 39

• Definition of primary gastrointestinal lymphoma:
• Primary gastrointestinal lymphomas exhibit no evidence of liver, spleen, mediastinal lymph node, or bone marrow involvement at the time of diagnosis

Question 40

B-cell lymphomas.

What is the Ten-year survival for patients with localized mucosal or submucosal disease?

What are 3 different types of B-cell lymphomas?

Answer 40

• B-cell lymphomas
• Ten-year survival for patients with localized mucosal or submucosal disease ≈85%
• 3 different types of B-cell lymphomas:

1) MALT (mucosa-associated lymphoid tissue)
* Stomach (55% to 60%); small intestine (25% to 30%), proximal colon (10% to 15%), and distal colon (up to 10%).

2) Immunoproliferative small-intestinal disease (IPSID)
* Mediterranean lymphoma

3) Burkitt lymphoma

Question 41

What are T-cell lymphomas associated with?

What is their prognosis like?

Answer 41

• T-cell lymphomas are associated with a long-standing malabsorption syndrome
• Prognosis is poor (11% five-year survival rate).

Question 42

What are 3 different types of mesenchymal tumours?

What is the five-year survival rate of leiomyosarcomas?

Answer 42

• 3 different types of mesenchymal tumours:

1) Lipomas
* Well-demarcated, firm nodules

2) Leiomyomas

3) Leiomyosarcomas
* Large, bulky, intramural masses that eventually fungate and ulcerate into the lumen or project subserosally into the abdominal space
* Five-year survival rate 50% to 60%

Question 43

What are the 3 zones the anal canal is divided into?

What are the commonest benign neoplasm of the anus?

Answer 43

• 3 zones the anal canal is divided into:
  1) Upper (covered with rectal mucosa)
  2) Middle (partially covered with a transitional mucosa)
  3) Lower (covered by stratified squamous mucosa)
• Warts (condyloma acuminata) are the commonest benign neoplasm of the anus

Question 44

What are 4 different types of malignant tumours (carcinomas) of the anal canal?

Answer 44

• 4 different types of malignant tumours (carcinomas) of the anal canal:

1) Basaloid pattern
* Immature proliferative cells derived from the basal layer of a stratified squamous epithelium

2) Squamous cell carcinoma
* Closely associated with chronic HPV infection

3) Adenocarcinoma
* Extension of rectal adenocarcinoma

4) Malignant Melanoma (very rare)