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MD3002 Pathology > GI tumours of the Lower Tract > Flashcards

GI tumours of the Lower Tract Flashcards

1
Q

What percentage of GI tumours are present in the small intestine?

A

3 - 6%

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2
Q

What percentage of SI benign tumours are adenomas?

A

25%

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3
Q

What are the different types of SI benign mesenchymal tumours?

A
  • Leiomyoma
  • Lipoma
  • Angioma
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4
Q

What are the different types of malignant SI tumours?

A
  • Adenocarcinoma and carcinoid

- Lymphoma and sarcoma

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5
Q

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

A
  • Non-neoplastic polyps

- Neoplastic - Adenoma

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6
Q

What are the different types of malignant colon and rectum tumours?

A
  • Adenocarcinoma (98%)
  • Carcinoid
  • Anal zone carcinoma
  • Lymphoma
  • Leiomyosarcomas
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7
Q

Who are likely to be affected by SI benign adenomas?

A

30 - 60 year old patients with occult blood loss

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8
Q

What is usually affected by SI benign tumours?

A

Ampulla of Vater (becomes enlarged and exhibits a velvety surface)

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9
Q

What can a SI adenoma become?

A

Has malignant potential to become an adenocarcinoma

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10
Q

Where do small intestine adenocarcinomas occur?

A

Duodenum

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11
Q

What age are patients usually affected by adenocarcinomas of the SI?

A

40 - 70 years old

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12
Q

What is the appearence of Adenocarcinomas of the SI?

A
  • Napkin-ring encircling pattern

- Polypoid exophytic masses

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13
Q

What happen can happen as a result of SI adenocarcinomas?

A
  • Intestinal obstruction
  • Cramping pain, nausea, vomitting, weight loss
  • may cause obstructive jaundice
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14
Q

What is the 5 year survival rate of SI adenocarcinomas?

A

70%

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15
Q

What can non-neoplastic polyps be divided into in the colon and rectum?

A
  • Hyperplastic (90%)

- Hamartomatous

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16
Q

What can neoplastic ‘adenomas’ be divided into in the colon and rectum?

A
  • Tubular
  • Villous
  • Tubulovillous
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17
Q

What age group are affected by hyperplastic polyps?

A

> 60

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18
Q

What is the appearence of hyperplastic polyps?

A
  • <5mm
  • Nipple-like, hemispheric, smooth, moist protrusions of the mucosa
    Histologically:
  • Well-formed glands and crypts
  • Lined by non-neoplastic epithelial cells
  • Most of which show differentiation into mature goblet or absorptive cells
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19
Q

Do non-neoplastic polyps (hyperplastic or hamartomatous) have malignant potential?

A

No

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20
Q

Who are affected by Hamartomatous polyps?

A

Children < 5

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21
Q

Where are hamartous polyps found?

A

80% in the rectum

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22
Q

What are hamartomatous polyps?

A
  • Beinign non-neoplastic tumours found mostly in rectum
  • Malformations of the mucosal epithelium and lamina propria
    Histologically:
  • Abundant cystically dilated glands
  • Inflammation is common
  • Surface may be congested or ulcerated
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23
Q

What are Peutz-Jeghers polyps caused by?

A
  • Peutz-Jeghers autosomal dominant syndrome

- Mutation of the gene STK11 (LKB1) located on chromosome 19

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24
Q

Where is affected by Peutz-Jeghers hamartomatous polyps?

A
  • Stomach 25%
  • Colon 30%
  • Small bowel
    Involve the mucosal epithelium, lamina propria, and muscularis mucosa (tend to be large and pedunculated)
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25
Q

What peutz-jeghers syndrome increase the risk of?

A
  • Pancreas
  • Breast
  • Lung
  • Ovary
  • Uterus carcinoma
    Polpyps themselves are hamartomatous and do not have malignant potential
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26
Q

What can neoplastic polyps - adenomas appear like?

A
  • Small, pedunculated lesions to large neoplasms that are usually sessile
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27
Q

Who are affected by neoplastic polyps - adenomas?

A
  • 20 - 30% before 40
  • Rising to 40 - 50% after age 60
  • Equal male to female ratio
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28
Q

What do neoplastic polyps - adenomas arise as a result of?

A

Epithelial prolifrative dysplasia

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29
Q

What can neoplastic polyps - adenomas be classified as?

A
  • Tubular adenomas (most common 75%)
  • Vilous adenomas (1-10%)
  • Tubulovillous adenoma (5-15%)
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30
Q

What are neoplastic adenomas a precursor lesion for?

A

Invasive colorectal adenocarcinomas

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31
Q

What is the risk of adenocarcinomas associated with in relation to adenomas?

A

Polyp size
- High risk (40%) in sessile villous adenomas > 4 cm
Histological architecture
Severity of epithelial dysplasia
- Severe dysplasia, when prsent, is often found in villous areas
IMPOSSIBLE FROM GROSS INSPECTION OF A POLYP TO DETERMINE ITS CLINICAL SIGNIFICANCE

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32
Q

What percentage of tubular adenomas are present in the colon?

A

90% also present in stomach and SI

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33
Q

How big are tubular adenomas?

A

Usually < 2.5 cm

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34
Q

What do tubular adenomas usually appear like?

A
  • Small tubular adenomas are smooth-contoured and sessile

- Larger ones tend to be coarsely lobulated and have slender stalks raspberry - like

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35
Q

How can tubular adenomas be removed?

A
  • Colonoscopy

- Metal hook put around it and burned and sucked out

36
Q

What do tubular adenomas appear like histologically?

A
  • Stalk is composed of fibromuscular tissue and prominent blood vessels
  • Presence of dysplastic epithelium, which lines glands as a tall, hyperchromatic, disordered epithelium that may show mucin vacuoles
  • Degree of dyslasia is low-grade
  • High-grade dysplasia may be present
  • Carcinomatous invasion into the submucosal stalk of the polyp constitutes invasive adenocarcinoma
37
Q

Who are affected by villous adenomas?

A

Older people

38
Q

Where are vilous adenomas found?

A

Commonly in the rectum and rectosigmoid

39
Q

What do villous adenomas appear like?

A
  • Sessile, up to 10cm

- Velvety or cauliflower - like masses projecting 1 to 3 cm above the surrounding normal mucosa

40
Q

What is the histological appearence of vilous adenomas?

A
  • Frond like villiform extensions of the mucosa
  • Covered by dysplastic, sometimes very disorderly columnar epithelium
  • All degrees of dysplasia may be encountered
  • When invasive carcinoma occurs (40%), there is no stalk as a buffer zone, and the invasion is directly into the wall of the colon
41
Q

What adenomas may be asymptomatic?

A
  • Colorectal tubular and tubolovillous adenomas

- Many are discovered during evaluation of anaemia or occult bleeding

42
Q

What adenoma is often discovered because of overt rectal bleeding?

A

Villous adenomas

43
Q

What is the metastatic potential of an intramucosal carcinoma with lamina propria invasion only?

A

Little or no metastatic potential

44
Q

When can endoscopic removal of a pedunculated adenoma be regarded as adequate?

A
  • The adenocarcinoma is superficial and does not approach the margin of axcision across the base of the stalk
  • There is no vascular or lymphatic invasion
  • The carcinoma is not poorly differentiated
45
Q

When can a a sessile polyp not be adequately resected by polypectomy?

A
  • If invasive adenocarcinoma further surgery may be required
46
Q

What are the chances of developing adenocarcinoma before age 30 with Familial Adenomatous Polyposis?

A

100% (total colectomy indicated)

47
Q

What mutation leads to FAP syndrome?

A

Mutations of the adenomatous polyposis coli (APC) gene on chromosome 5q21-22

48
Q

How many colonic adenomas develop on the mucosal surface as a result of FAP?

A

500 to 2500

49
Q

What are the vast majority of polyps in patients with FAP?

A

Tubular adenomas

50
Q

What percentage of all cancers in the colon are adenocarcinomas?

A

98%

51
Q

What demographics are affected by colorectal carcinomas?

A
  • peak between 60 - 79
  • Rectum more male than female 1.2 : 1
  • More proximal tumours male to female ratio 1:1
52
Q

Where are the highest death rates of colorectal carcinoma?

A
  • US, Australia, NZ, Eastern European countries
53
Q

How does colorectal cancer rank in terms of death rates in comparison with other cancers

A

3rd

- Behind lung and bronchus (1st) and breast (woman), prostate (men).

54
Q

What dietary factors increase the risk of colorectal cancer?

A
  • Excess dietary caloric intake relative to requirements
  • Low content of vegetable fibre
  • High content of refined carbohydrates
  • Intake of red meat
  • Decreased intake of protective micronutrients
55
Q

Where are colorectal cancers located?

A
  • Rectosigmoid 55%
  • Caecum / Ascending 22%
  • Transverse 11%
  • Descending 6%
  • Other sites 6%
56
Q

What do all colorectal cancers begin as?

A

Carcinoma in situ lesions

57
Q

What are the features of tumours in the proximal colon?

A
  • Polypoid, exophytic masses
  • Obstruction is uncommon (as caecum and ascending lumen are wide)
  • Penetrate the bowel wall as subserosal and serosal white, firm masses
58
Q

What are the features of tumours in the distal colon?

A
  • Annular, encircling lesions (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
  • Penetrate the bowel wall as subserosal and serosal white, firm masses
59
Q

What is the charecteristic lesion of people with adenocarcinoma of colon with barium enema technique?

A

Apple-core lesion

60
Q

What can the histology look like for patients with colonic adenocarcinoma?

A
  • May range from tall, columnar cells resembling their counterparts in adenomatous lesions to
  • Undifferentiated, frankly anaplastic masses
  • Many produce mucin (can be found on DRE)
  • Invasive tumour incites a strong desmoplastic stromal response
61
Q

What can the clinical features be of colonic adenocarcinomas? (both caecumand right colonic + left-sided lesions)

A
  • Asymptomatic for years
  • Iron-deficiency anaemia in an older male means gastrointestinal cancer unless proven otherwise
  • Systemic manifestations such as weakness, malaise, and weight loss signify more extensive disease
62
Q

What clinical features can differentiate colonic adenocarcinomas of the caecum and right colon and left-sided lesions?

A

Caecum and right colonic
- Fatigue, weakness, and iron-deficiency anaemia
Left-sided lesions
- Occult bleeding, changes in bowel habit, or crampy left lower quadrant discomfort

63
Q

A 65 year old man’s blood test comes back and presents with iron-deficiency anaemia what is the likely diagnosis?

A

GI cancer until proven otherwise

64
Q

How do all colorectal cancers spread?

A
  • Direct extension into adjacent structures

- Mestasis through lymphatics and blood vessels

65
Q

Where can colorectal tumours spread to?

A
  • Regional lymph nodes
  • Liver
  • Lungs
  • Bones
  • Serosal membrane of the peritoneal cavity
  • Brain
  • Other areas
66
Q

How can cancer be classified using Duke’s staging?

A

A - confined to the submucosa or muscle layer (90+%)
B - spread through the muscle layer, but does not yet involve the lymph nodes
C - involving lymph nodes (35%)
Percentages = 5 year survival rate

67
Q

What are carcinoid tumours of the GI tract derived from?

A

Endocrine cells

68
Q

What percentage of GI tumours are carcinoid tumours?

A

2% of colorectal malignancies but almost 1/2 of SI malignant tumours

69
Q

Who is largely affected by carcinoid tumours?

A

> 60

70
Q

What kind of tumour has no reliable histological difference between malignant and benign?

A

Carcinoid tumours of the GI tract

71
Q

What does the aggresive behaviour of carcinoid tumours correlate with?

A
  • Site of origin
  • Depth of local penetration
  • Size of local tumour
  • Histological features of necrosis and mitosis
72
Q

What is the most common site of GI carcinoid tumour?

A

Appendix (can appear in SI - usually ileum, rectum, stomach and colon)

73
Q

What do carcinoid tumours appear like in the GI tract?

A
  • Usually solitary lesion (except ileum and stomach - multicentric)
  • Intramural or submucosal masses that create small polypoid or plateau-like elevations > 3 cm
  • Solid, yellow-tan appearence on transection
74
Q

What may the histolog look like of carcinoid tumours of the GI tract?

A
  • 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
  • By electron microscopy tumour cells contain membrane-bound secretory granules with dense-core granules in the cytoplasm
75
Q

What are the clinical features of carcinoid tumours?

A

Rarely produce local symptoms

  • Caused by angulation or obstruction of the small intestine
  • Some neoplasms are associated with a distinctive carcinoid syndrome (from excess of serotonin)
  • Cutaneous flushes and apparent cyanosis
  • Diarrhoea, cramps, nausea, vomitting
  • Cough, wheezing, dyspnoea
76
Q

What carcinoid tumours do not metastasize?

A

Appendiceal and rectal

77
Q

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

A

90%

78
Q

Carcinoids affecting what region 90% of the time have spread to lymph nodes and distant sites at the time of diagnosis?

A
  • Ileal
  • Gastric
  • Colonic
79
Q

What is the definition of a GI lymphoma?

A

Primary GI lymphomas exhibit no evidence of liver, spleen, mediastinal lymph node, or bone marrow involvement at the time of diagnosis

80
Q

What are mesenchymal lipomas?

A

Well-demarcated, firm nodules <4 cm arising withinn the submucosa or muscularis propria

81
Q

What are mesenchymal leiomyosarcomas?

A
  • Large, bulky, intramural masses that eventually fungate and ulcerate into the lumen or project subserosally into the abdominal space
  • 5 year survival rate 50 - 60%
82
Q

What are the 3 types of mesenchymal tumour?

A
  • Lipomas
  • Leiomyomas
  • Leiomyosarcomas
83
Q

What are the 3 zones of the anal canal?

A
  • Upper (covered with rectal mucosa)
  • Middle (partially covered eith transitional mucosa)
  • Lower (covered by stratified squamous mucosa)
84
Q

What are the most common benign neoplasms of the anus?

A

Warts (condyloma acuminata)

85
Q

What are the malignant carcinomas of the anal canal?

A

Basaloid pattern
- Immature proliferative cells derived from the basal of a stratified squamous epithelium
Squamous cell carcinoma
- Closely associated with chronic HPV infection
Adenocarcinoma
- Extension of rectal adenocarcinoma
Malignant Melanoma (v. rare)

MD3002 Pathology (19 decks)

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