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GI > 25. Tumors of the Small and Large Bowel > Flashcards

25. Tumors of the Small and Large Bowel Flashcards

1
Q

Though the small intestine makes up 75% the length of the GI tract, what % of the tumors are found there?

A

3-6%

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2
Q

What is the most common tumor of the SI?

A

Adenoma near the ampulla

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3
Q

What are four RFs for small intestine adenocarcinoma?

A

Crohn’s disease
Adenomas
Celiac disease
Familial polyposis syndrome

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4
Q

What is the most common non-epithelial tumor in the GI tract? What is it derived from?

A

GIST

Mesenchymal origin, from interstitial cells of Cajal (pacemaker cells)

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5
Q

What are three syndromes associated with GIST?

A
  1. Carney triad: GIST, pulmonary chondroma, extra-adrenal paragnaglioma
  2. Neurofibromatosis
  3. Carney-Stratakis syndrome
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6
Q

What can be used to treate GIST and CML?

A

Gleevec/imatinib

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7
Q

Where is GIST most commonly located?

A

Stomach (60%)
SI (30%)
Colon (4%)

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8
Q

What % of GIST tumors have a c-kit mutation?

A

85%

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9
Q

What are three specific markers for GIST?

A

c-kit (CD117)
DOG1
CD34

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10
Q

What are three muscle markers that can be used for GIST but are not necessarily specific?

A

Actin
Desmin
S-100

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11
Q

What two tyrosine kinase receptors can get mutated in GIST, and in what region of the receptor?

A

C-kit: juxtamembrane domain

PDGFRA: tyrosine kinase II domain

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12
Q

What are neuroendocrine tumors of the GI that secrete bioactive compounds?

A

Carcinoid tumors

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13
Q

What are components of carcinoid syndrome?

A 
Vasomotor distrubances 
Intestinal hypermotility (diarrhea)
Wheezing
Hepatomegaly
Cardiac involvement
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14
Q

What condition can lead to MALT lymphoma?

A

H. pylori gastritis

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15
Q

What is a polyp?

A

Epithelium-derived tumor mass which protrudes into the gut lumen

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16
Q

What are the two main types of polyp by shape?

A

Pedunculated polyp

Sessile polyp

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17
Q

A non-neoplastic polyp is a result of:

A

Abnomal mucosal maturation, inflammation, architectural distortion
**no malignant potential

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18
Q

Neoplastic polyps arise from:

A

Proliferation and dysplasia (adenomas)

**precursor for carcinoma

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19
Q

What are the three main types of non-neoplastic polyps?

A

Hamartomatous
Inflammatory
Lymphoid

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20
Q

What is a hamartoma?

A

Benign tumor that is composed of mature, histologically normal elements that grow in a disorganized manner due to developmental error

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21
Q

What is a choistoma?

A

Like a hamartoma, but in an abnormal location

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22
Q

Where do 80% of juvenile, hamartomatous polyps occur? Shape?

A

Rectum

Pedunculated (1-3 cm)

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23
Q

Histologic appearance of juvenile, hamartomatous polyps

A

Expanded lamina propria with variable inflammation
Abundant cystically dilated and tortuous glands
*non-neoplastic

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24
Q

What is Juvenile polyposis syndrome?

A

Over 5 juvenile polyps in the stomach, SI, colon, rectum

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25
Q

What mutations are associated with juvenile polyposis syndrome?

A

SMAD4 (20%)
BMPR1A (20%)
**NOT PTEN

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26
Q

Juvenile polyposis syndrome is associated with risk for:

A

Adenomas

10-50% lifetime incidence of colon cancer

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27
Q

What mutation is Peutz-Jeghers syndrome associated with (hamartomatous polyps)

A

STK11

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28
Q

What is seen in Peutz-Jeghers syndrome?

A

Multiple GI hamartomatous polyps

Hyperpigmentation–mucosal and cutaneous (fingers)

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29
Q

What is there an increased risk for with Peutz-Jeghers syndrome?

A

Intussusception

Cancer of the pancreas, breast, lung, ovary, uterus (50% cumulative lifetime risk for cancer)

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30
Q

What are the characteristics of Peutz-Jeghers Polyp?

A

Large and pedunculated
Connective tissue and smooth muscle extends into the polyp
Abundant glands rich in goblet cells

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31
Q

What is Cowden syndrome?

A

AD condition with:

  • Hamatomatous GI polyps
  • Facial trichilemmomas
  • Oral papillomas
  • Acral keratoses
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32
Q

What is Cowden syndrome associated with a risk for?

A

Thyroid and breast cancer

**polyps themselves have no malignant potential

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33
Q

What is Cronkhite Canada syndrome?

A

Non-herediatry syndrome with

  • GI hamartomatous polyps
  • Nail atrophy and alopecia (ectodermal abnormalities)
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34
Q

What are inflammatory polyps?

A

Psuedopolyps that form from regenerating mucosa adjacent to ulceration (usually with severe IBD)

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35
Q

What are lymphoid follicles?

A

Mucosal bumps that are caused by intramucosal lymphoid follicles (normal)

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36
Q

What are the two serrated polyps?

What are the two types of polyps with malignant potential?

A

Hyperplastic and sessile serrated polyps

Sessile serrated polyps and adenomatous polyps

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37
Q

What are serrated polyps?

A

Smooth protrusions of mucosa, usually at the tops of mucosal folds
Serrated lumnia and increased numbers of goblet cells

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38
Q

Where are most serrated polyps found?

A

Rectosigmoid colon

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39
Q

What is the prevelance of the two types of serrated polyps?

A

Hyperplastic 60-90% (MC)

Sessile serrated 10-30%

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40
Q

What kind of mutation is associated with sessile serrated polyps?

A

BRAF V600E mutations

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41
Q

What do adenomas/adenomatous polyps arise from?

A

Arise from epithelial proliferative dysplasia

Precursor lesions for adenocarcinoma

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42
Q

What are the three architectural types of adenomas/adenomatous polyps?

A

Tubular adenoma
Villous adenoma
Tubulovillous adenoma

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43
Q

Prevalence of adenomas?

With adenomas, __fold greater risk for developing carcinoma

A

Common, 40-50% after 60

4 fold

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44
Q

Morphology and location of tubular adenomas

A

Small and pedunculated from dysplastic epithelium (elongated, psuedostratified, hyperchromatic nuclei with loss of mucin production)
90% in the colon

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45
Q

Morphology and location of villous adenoma?

A

Villous projections that are large and sessile

Retrosignoid colon of older people

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46
Q

Why does invasion occur more readily with villous adneoma than tubular?

A

No stalk to act as a buffer zone–cancer invasion occurs directly into the colon wall, lymphatics

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47
Q

While cancer is rare in TAs under 1 cm, the risk of cancer approaches __% in sessile, villous adenomas over 4 cm

A

40%

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48
Q

Clinical presentation of adenomatous polyps

A

Asymptomatic or

Present with rectal bleeding or anemia

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49
Q

When is endoscopic removal of pendunculated adenomatous polyps sufficient?

A
  • Resection margins negative
  • No vascular or lymphatic invasion
  • Carcinoma not poorly differentiated
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50
Q

Colon and rectum cancer is the ___ deadliest cancer

A

Second

51
Q

98% of colorectal cancer is what type?

A

Adenocarcinoma

52
Q

Where are the most common locations for colorectal cancer?

A 
Rectosigmoid colon (55%)
Cecum and ascending colon (22%)
Transverse colon (11%)
Descending colon (6%)
53
Q

In what geographic locations are the highest death rates from colorectal cancer?

A 
US
Australia
New Zealand
Eastern Europe
**linked to diet
54
Q

What dietary practices are risk factors for colorectal carcinoma?

A 
Excess dietary intake
Low fiber
High content of refined carbs
Red meat
Decreased intake of nicronutrients
Obesity and physical inactivity
55
Q

Presentation of right sided colon cancer? Type of lesions?

A

Non-obstructive
Fatigue, weakenss, IDA
**Polypoid, exophytic lesions

56
Q

Presentation of left sided colon cancer? Type of lesions?

A

Obstructive
Occult bleeding, changes in BMs, abdominal discomfort
Annular “napkin ring” constrictions
**Infiltrative

57
Q

What classic presentation is colon cancer until proven otherwise?

A

IDA in a older male

58
Q

What is the idea behind the ‘adenoma-carcinoma sequence’?

A

Populations with a high prevalence of adenomas have a high prevalence of colon cancer, and vice versa
Distribution of the two is similar

59
Q

What is typically the first mutation to occur in the multi-hit devo of adenoma-carcinoma?

A

Inactivating mutation in APC (5q11)

**also beta catenin

60
Q

What is the result of dysfunction of APC?

A

Increased WNT signaling, which leads to decreased cell adhesion and increased cell proliferation

61
Q

What mutation occurs late in the multi-hit development of adeomas and carcinoma?

A

Loss of p53

62
Q

Along with p53, APC, and beta catenin, what are other mutations involved in the development of colorectal cancer?

A

K-RAS
LOH
SMAD2 and 4

63
Q

When colorectal cancer is insidiously infiltrative and difficult to identify grossly, what is this usually associated with?

A

Ulcerative colitis

64
Q

What does that T of TMN classification represent?

A

Depth of invasion

65
Q

What are the T stages of the TMN classification?

A

Tis: In situ (LP invasion)
T1: Invasion of submucosa
T2: Invasion of muscularis propria
T3: Penetration of muscularis propria into serosa
T4: Invasion into other structures/organs

66
Q

What are stages 0-IV of colon carcinoma

A 
Stage 0: in situ
Stage I: T1 or T2, N0, M0
Stage II: T3 or T4, N0, M0
Stage III: Any T, + nodes, M0
Stage IV: Any T, any N, M1
67
Q

What is the difference between N1 and N2 in stage III?

A

N1: 1-3 positive LNs
N2: 4 or more positive LNs

68
Q

What is the most important prognostic factor for colorectal carcinoma?

A

Stage of the tumor at the time of diagnosis

69
Q

What is the 5 yr survival for stage I, II, III, IV?

A

I: 93.2%
II: 85%
III: 70%
IV: 8.1%

70
Q

What are the different ways the colon carcinoma can metastasize?
What % of patients have mets at the time of dx?

A
  • Direct extension into adjacent structures
  • Met through LNs and vessels
  • *25-30%
71
Q

What are the four non-specific agents that can be used for colorectal carcinoma (more SEs)

A

5FU
Capecitabine
Irinotecan
Oxaliplatin

72
Q

What are the three drugs that can be used for targeted therapy of colorectal cancer (picked based on the mutation prolife of the cancer present)

A

Bevacizumab
Cetuximab
Panitumumab

73
Q

What are the two types of biomarkers with respect to their function?

A

Prognostic: info about the patient’s overall outcome, regardless of therapy
Predictive: info about the effects of a particular therapeutic intervention

74
Q

What receptor stimulates key processes involved with tumor growth and progression–proliferation, angiogenesis, invasion, and metastasis?

A

EGFR

**overexpressed in a range of solid tumors

75
Q

What 3 major pathways are activated by EGFR?

A
  1. RAS-RAF-MAP kinase
  2. PI3K-AKT
  3. PLCy
76
Q

What are the three domains of EGFR?

A 
Extracellular domain
Transmembrane domain
Intracellular domain (tyrosine kinase)
77
Q

What are the 4 subsets of EGFR?

A

ErbB1/EGFR/Her1
ErbB2/Her2
ErbB3/Her3
ErbB4/Her4

78
Q

What subset of EGFR is expressed in COLON cancer, lung, and head and neck cancers?

A

ErbB1/EGFR/Her1

79
Q

What are the two monoclonal antibodies to EGFR?

A

Cetuximab

Ranitumumab

80
Q

It is not the EGFR expression that dictates response to anti-EGFR therapy, but rather:

A

Constituativly active proteins downstream of EGFR, like K-RAS, B-Raf, PI3K, and PTEN

81
Q

What is the major negative predicator of efficiency of EGFR monocloncal antibody tx (cetuximab and reanitumab)?

A

K-RAS mutation **

BRAF mutation

82
Q

What are the uncommon and autosomal dominant herediatary syndromes that involve the GI tract?

A
  1. Peutz-Jeghers, Cowden disease, Juvenile
  2. FAP- Gardner’s and Turcot’s syndromes
  3. MYH associated polyposis (MAP)
  4. Lynch syndrome
83
Q

Inheritance and penetrance of familial adenomatous polyposis

A

Autosomal dominant

Very penetrant

84
Q

How many colonic adenomas are typically present in FAP?

A

500-2,500 (minimum of 100)

85
Q

Tx for FAP?

A

Prophylactic colectomy, because colon adenocarcinoma occurs in 100%

86
Q

FAP is due to inheritance of germline mutations in:

A

APC gene in chrom 5q11

87
Q

What % of people with FAP have no fam hx (de novo, somatic mutations)

A

25%

88
Q

What is the age of onset for FAP?

A

median 16
Range 5-38 years
Colorectal cancer in late 30s early 40s

89
Q

What is attenuated FAP

A

<100 polyps

Some residual low level of APC resulting in fewer polyps

90
Q

What is Gardner syndrome?

A

Adenomatous polyposis
Osteomas
Epidermoid cysts
Desmoid tumors

91
Q

What is Turcot syndrome?

A

Adenomatous polyposis

Medulloblastoma

92
Q

Where in the chromosome coding for APC are mutation leading to classical FAP? Attenuated? Garner?

A

Near N terminal
Near C terminal
Between (causes desmoids)

93
Q

What is a herediatary colorectal cancer syndrome that looks like attenuated FAP (20-100 adenomatous polyps) but is caused by a different mutation (not APC)

A

MYH associated polyposis (MAP)

94
Q

Inheritance pattern for MYH associated polyposis. Age of presentation

A

Autosomal recessive

Older age of presentation

95
Q

MAP is due to mutations in the MYH gene, which encodes what kind of protein?

A

DNA repair protein involved in base excision repair (repairs oxidation-induced DNA damage by removing A mis-paired with G)

96
Q

What are the two common mutations in MYH associated polyposis?

A

494A->G
1145G->A
**present in 85-90%

97
Q

What is lynch syndrome associated with an increased risk for?

A

Colorectal cancer

Extra-intestinal cancer: endometrial cancer, ureter, renal pelvis)

98
Q

What is the genetic defect in lynch syndrome?

A

DNA mismatch repair genes (microsatellite instability pathway)

99
Q

What is Muir-Torre syndrome?

A

Subtype of Lynch syndrome

Associated with multiple sebaceous adenomas, sebaceous carcinomas, and keratoacanthomas

100
Q

What are two histological presentation of Lynch syndrome tumors?

A

Mucinous features and chronic inflammation

Mucionous faatures and signet ring features

101
Q

What is the role of MSH2 and MSH6? PMS2 and MLH1

A

Find the mismatch

Read the mismatch and remove mutant strand

102
Q

What is the dominant protein in the MSH2/6 relationship?

MLH1/PMS2?

A

MSH2

MLH1

103
Q

What happens with a sporadic (12%) or hereditary (3%) loss of mismatch repair (MMR) function?

A

Random accumulation of mutations during cell divisions
Mutant in important oncogenes/tumor suppressor genes
Further acceleration of tumor devlopment
Cancer

104
Q

What is negative IHC with a MSH2 mutation?

A

MSH2 negative

MSH6 negative

105
Q

What is negative with a MSH6 mutation?

A

MSH6

106
Q

What is negative with a PMS2 mutation?

A

PMS2

107
Q

What is negative with a MLH1 mutation?

A

MLH1

PMS2

108
Q

Interpretation of a tumor that is + for MSH2, MSH6, MLH1, PMS2

A

Sporadic cancer, LS unlikely

109
Q

Interpretation of a tumor that is - for MLH1, PMS2? Etiology?

A

LS or sporadic caner

MLH1 mutation or MLH1 hypermethylation

110
Q

Interpretation of a tumor that is - for MSH2 and MSH6? Etiology

A

LS

MSH2 mutation

111
Q

Interpretation of a tumor that is - for MSH6? Etiology

A

LS

MSH6 mutation

112
Q

Interpretation of a tumor that is - for PMS2? Etiology

A

LS

PMS

113
Q

What are sensitive markers for defective function of mismatch repair?

A

Microsatellites: with DNA slippage, MMR should repair the loss of DNA. Failure of system leads to variation in the size of microsatellites

114
Q

What are the three outcomes of microsatellite testing?

A

Microsatellite stable (MSS): no markers show MSI
Microsatellite instability-LOW (MSI-L): one marker shows MSI
Microsatellite instability-HIGH (MSI-H): at least 2 markers show MSI

115
Q

What is the difference in the response of MSI-L vs MSI-H to adjuvant chemo?

A

MSI-L have better outcomes with adjuvant chemo

MSI-H have better outcomes without adjuvant chemo

116
Q

What mutation has never been reported in a patient with lynch syndrome, but it present in 68% of patients with MSI CRC that is not related to lynch syndrome?

A

BRAF mutation

117
Q

Do must people with MSI phenotypes and CRC have sporadic mutations or lynch syndrome?

A

SPORADIC

118
Q

What are the types of cancer that can occur in the anal canal?

A 
Basaloid carcinoma
Squamous cell carcinoma
Adenocarcinoma
Paget's disease
Small-cell carcinoma
Melanoma
119
Q

What is the MC tumor of the appendix?

A

Carcinoid (20-39 yrs)

120
Q

What is a mucocele?

A

Obstructed appendix containing insipissated mucin (not truely a tumor)

121
Q

What is a mucinous cystadenoma of the appendix?

A

Mucus secreting epithelial tumor of the appendix

122
Q

Where in the appendix are carcinoid tumors found?

A

At the distal tip

123
Q

What is a condition that can result from mucin produced by mucinous adenocarcinoma of the appendic?

A

Psuedomyxoma peritonei: mucin into the peritoneal cavity, encasing the organs

GI (28 decks)

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