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GI/Nutrition > Neoplasms of the Small & Large Bowel > Flashcards

Neoplasms of the Small & Large Bowel Flashcards

1
Q

What is the most common small intestine neoplasm?

A

Adenoma

75% length of GI

3-6% of GI tumors

Mesenchymal tumors are more rare: lipoma, GIST, lymphoma

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2
Q

What are the risk factors for small intestine Adenocarcinoma?

A
  • Crohn’s disease
  • Adenomas
  • Celiac disease
  • Familial Polyposis Syndrome
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3
Q

What is the most common non-epithelial (soft tissue) tumor in the GI tract?

A

GIST

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4
Q

GIST

  • Origin
  • May be seen in
  • Treatment
A
  • Mesenchymal origin (intestinal cells of Cajal - pacemaker cells)
  • May be seen in:
    • Carney triad
    • Neurofibromatosis
    • Carney-Stratakis syndrome
  • Gleevec (Imatinib)
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5
Q

GIST

  • IHC Markers
  • Muscle Markers
A
  • CD117 (c-KIT), DOG1, CD34
  • Actin, Desmin, S-100
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6
Q

GIST Mutations

A
  • c-KIT (80%), PDGFRA (5-10%)
  • Tyrosine kinase receptors
  • Ligand –> receptor dimerizes –> intracellular domains autophosphorylate –> constitutive activation of kinase in presence/absence of ligand
  • Gain-of-function mutation
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7
Q

What are the symptoms of carcinoid syndrome?

What becomes elevated?

A
  • Neuroendocrine tumor
  • Symptoms
    • Vasomotor disturbances
    • Intestinal hypermotility
    • Wheezing
    • Hepatomegaly
    • Cardiac involvement
  • Serotonin (5-HT) elevated
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8
Q

What is an intestinal polyp?

A

Epithelium-derived tumor mass

Protrudes into gut lumen

Pedunculated = stalk w/ polyp

Sessile = flat polyps that grow upward (no stalk)

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9
Q

What is the difference between a non-neoplastic polyp & neoplastic polyp?

A
  • Non-neoplastic polyp
    • Abnormal mucosal maturation
    • Inflammation
    • Distorted architecture
    • No malignant potential
  • **Neoplastic polyp **
    • Proliferation & dysplasia (adenomas)
    • Precursor of carcinoma
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10
Q

What are some examples of non-neoplastic polyps?

A
  • Hamartoma
  • Juvenile polyp
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11
Q

What is a hamartoma?

A
  • Benign tumor
  • Mature, histologically normal elements from that site growing in a disorganized manner
  • Developmental error
  • Occurs at many sites
  • Contrast w/ choristomas (haphazard tissue in wrong place)
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12
Q

What is a juvenile polyp?

What age group does it most commonly present?

Where in the GI tract does it present?

A
  • Kids <5 YO
  • 80% rectum
  • Pedunculated (1-3 cm)
  • Expanded LP w/ variable inflammation
  • Abundant cystically dialted, tortuous glands
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13
Q

What is the inheritance of Juvenile Polyposis Syndrome?

A

Autosomal dominant

Gain-of-function mutations

SMAD4 (20%)

BMPR1A (20%)

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14
Q

What is Juvenile Polyposis Syndrome?

A
  • Multiple juvenile polyps
    • >5
    • 5-100
  • Stomach, small intestine, colon, rectum
  • 10-15% lifetime incidence of colon cancer
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15
Q

Peutz-Jeghers polyps (do/don’t) have malignant potential

A

**Don’t **

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16
Q

A patient presents to you with multiple GI polyps and hyperpigmentation around their mouth & on their fingers? What do they likely have?

A

**Peutz-Jeghers Syndrome **

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17
Q

What does a Peutz-Jeghers Polyp look like on histology?

A
  • Large & pedunculated
  • Connective tissue & smooth muscle extends into the polyp
  • Abundant glands rich in goblet cells
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18
Q

Inheritance & Risk of Peutz-Jeghers Syndrome

A
  • Autosomal dominant (STK11)
  • Increased risk of intussusception
  • Increased risk of cancer
    • Pancreas, breast, lung, ovary, uterus
  • 50% cumulative lifetime risk of cancer
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19
Q

What are some clinical features of Cowden Syndrome?

A
  • Facial trichilemmomas
  • Oral papillomas
  • Acral keratoses
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20
Q

Inheritance & Risk of Cowden Syndrome

A
  • Autosomal dominant
  • Hamartomatous GI polyps
  • Risk of thyroid & breast cancer
  • Polyps themselves have _no malignant potential _
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21
Q

What is Cronkite-Canada?

How do these patients present?

A
  • Non-hereditary
  • GI Hamartomatous polyps
  • Ectodermal abnormalities
    • Nail atrophy
    • **Alopecia **
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22
Q

What is the difference between Inflammatory Polyps & Lymphoid Polyps?

A
  • Inflammatory Polyps
    • Pseudopolyps
    • Regenerating mucosa adjacent to ulceration
    • Severe IBD
  • Lymphoid Polyps
    • Mucosal bumps caused by intramucosal lymphoid follicles
    • Normal
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23
Q

What are Serrated Polyps? What do they look like?

A
  • Smooth protrusions of mucosa at tops of mucosal folds
  • Rectosigmoid colon (>50%)
  • “Serrated” lumina
  • Increased # of goblet cells
  • Small (<5 mm diameter)
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24
Q

What is the difference between Hyperplastic & Sessile Serrated polyps?

A
  • Hyperplastic
    • 60-90%
    • Distal
    • No malignant potential
  • Sessile Serrated
    • 10-30%
    • Proximal
    • High malignant potential
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25
What are the genetics of Sessile Serrated Polyps?
* **BRAF V600E** mutations * Methylation * Microsatellite instability
26
What is the difference between Hyperplastic & Sessile Serrated Polyps with regards to **growth**?
* **Hyperplastic Polyps** * Grows from bottom to top * Growth rate faster than death rate of normal colonic cells * Serrations at tips of crypts * **Sessile Serrated Polyps** * Grows up & down * Cystically dilated glands * Bottom growing faster than cells dying * Horizontal growth along BM
27
What is this?
* **HIGH GRADE DYSPLASIA** * Large "salt & pepper" nuclei * Elongated, crowded, stretched out * Mitotic figures present in mucosa * *Carcinoma in situ*
28
What are Adenomatous Polyps? What are the 3 architectural types? Demographics?
Arise from epithelial proliferative dysplasia Precursor lesions for adenocarcinoma **Tubular, villous, tubulovillous ** \>60 YO, M = F
29
What is a Tubular Adenoma?
* Tubular glands * Small, pedunculated * Colon (90%) * Single or multiple * Rarely \>2.5 cm
30
What does a Tubular Adenoma look like histologically?
* **Dysplastic epithelium** * Elongated, pseudostratified * Hyperchromatic nuclei * Loss of mucin production
31
What is a Villous Adenoma?
* Villous projections * Large, sessile * Older people * Rectosigmoid colon * *Invasive carcinoma* * No stalk for buffer zone * Cancer invasion direct into colon wall * _\<_10 cm diameter
32
What does a Villous Adenoma look like histologically?
flat, polypoid fungating, irregular
33
What is the relative cancer risk with polyps?
\<1cm = rare **sessile, villous adenomas \>4cm (40%)** high grade dysplasia in villous areas high grade dysplasia/carcinoma can be in any polyp
34
What is the clinical significance of an Intramucosal Carcinoma vs. Invasive Carcinoma?
* Asymptomatic vs. rectal bleeding/anemia * **Intramucosal carcinoma** * Invades LP * No metastatic potential * **Invasive carcinoma ** * Pedunculated adenoma (*endoscopy*) * Sessile polyp (*partial colectomy*)
35
Regardless of whether carcinoma is present, the only adequate treatment for adenoma is \_\_\_\_\_\_\_\_\_\_.
**Complete Resection **
36
Colorectal Cancer * Stats * Distribution * Risk
* Stats * 98% adenocarcinoma * 90% diagnosed \>50 YO * Distribution * Rectosigmoid colon (55%) * Cecum & ascending colon (22%) * Risk factors * Excess dietary caloric intake * Low fiber * High refined carbs * Red meat * Micronutrients * Obesity, physical inactivity
37
Right-sided vs. Left-sided Colon Cancer
* **Right-Sided** * Non-obstructive * Fatigue, weakness, iron deficiency anemia * Polypoid, exophytic lesions * **Left-Sided** * May be obstructive * Occult bleeding, changes in bowel habit, abdominal discomfort * **Annular "napkin ring" constrictions** * Infiltrative
38
You have a patient who is an older adult male w/ iron deficiency anemia. What is your primary concern?
**Colon Cancer ** \*suspicion until proven otherwise\*
39
What is the Adenocarcinoma Sequence?
* Development of carcinoma from adenomatous lesions * High prevalence of adenomas ~ high prevalence of colon cancer * Cancer risk directly related to # of adenomas * **Colorectal carcinogenesis** * Accumulation of mutations more important than specific order
40
What is the Adenocarcinoma Pathway? (genes, etc.)
Inactivated **APC** (\>80%) 50% of cancers w/APC mutations: **ß-catenin** mutations Dysfunction of APC --\> increased **WNT** signaling --\> decreased cell adhesion --\> increased cellular proliferation Loss of **p53** late in colon carcinogenesis
41
What are some characteristics of **Infiltrative** Colorectal Cancer?
* Infrequent, infiltrative & difficult to identify * Pattern associated with Ulcerative Colitis * Exceedingly aggressive * Spread at early stage in evolution
42
The most important prognostic indicator of colorectal carcinoma is the ______________ at the time of diagnosis.
Extent of tumor (**stage**) Stage = T + N + M
43
What are the 4 types of tumor classification?
* TIS = mucosa * T1 = submucosa * T2 = muscularis propria * T3 = serosa
44
What is the T, N & M for: * Stage 0 * Stage I * Stage II * Stage III * Stage IV
45
What is the 5 year survival for the Colorectal Cancer Staging?
* Stage I (93.2%) * Stage II (85%) * Stage III (70%) * Stage IV (8.1%)
46
How does colon cancer normally metastasize?
* Direct extension into adjacent structures * Metastases through lymph nodes & vessels * Regional **lymph nodes, liver, lungs, bones** * Metastatic spread at presentation (25-30%)
47
What are the targeted therapeutic options for treating Colorectal Carcinoma?
Bevacizumab Cetuximab Panitumumab
48
What are the **prognostic** & **predictive** biomarkers for adjuvant therapy of colorectal cancer?
* **Prognostic** * Provide information about patient's overall outcome * Regardless of therapy * **Predictive** * Give information about the effects of a particular therapeutic intervention
49
How and why is **EGFR** a key target in cancer?
* Activation stimulates key processes involved in tumor growth & progression * Proliferation * Angiogenesis * Invasion * Metastasis * Overexpressed in a range of solid tumors
50
What 3 major pathways are activated by EGFR?
RAS-RAF-MAP kinase P13K-AKT PLC-gamma
51
What is the structure of EGFR? What are the two most important members of the EGFR family involved in cancer?
* Transmembrane domain + intracellular domain * ErbB1/EGFR/Her1 * ErbB2/Her2/Neu * **Breast cancer **
52
In what circumstance would a patient be responsive to moAB therapy vs. resistant to moAB therapy?
* Sensitive to moAB therapy * Transient response * 12-18 mo * moAB therapy resistant * Mutation in **downstream effector** * TUMOR GROWTH * Shouldn't give the drug
53
\_\_\_\_\_\_ is the major negative predictor of efficacy in EGFR moAB therapy.
**KRAS mutation**
54
\_\_\_\_\_\_ correlates w/ poor diagnosis & lack of response to EGFR moAB therapy.
**BRAF mutation**
55
What are some hereditary diseases involving the GI tract?
* Peutz-Jeghers Syndrome, Cowden Disease, Juvenile Polyposis Syndrome * Familial Adenomatous Polyposis * Gardner's Syndrome * Turcot's Syndrome * MYH Associated Polyposis * Lynch Syndrome/HNPCC
56
What is the inheritance of Familial Adenomatous Polyposis?
* **Autosomal dominant ** * Germline mutations in **APC gene** * ~25% FAP patients have no FaHx * 2nd normal allele mutated * **Loss of heterozygosity ** * Tumor formation
57
Familiar Adenomatous Polyposis * Characteristics * Prevalence * Age
* **500-2,000 colonic adenomas** * 100 minimum * Colon adenocarcinoma (100%) * Prophylactic colectomy required * Adenomas elsewhere in GI tract * Median age: **16 YO** * Age range: 5-38 YO * Age of onset of colorectal cancer * Late 30s, early 40s
58
What are the variants of FAP?
Attentuated FAP (\<100) Gardner's syndrome Turcot syndrome
59
What is Gardner's Syndrome?
* Adenomatous polyposis PLUS: * Osteomas * Epidermoid cysts * Desmoid tumors
60
What is Turcot Syndrome?
Adenomatous polyposis + medulloblastoma
61
FAP mutations * Classical * Attenuated * Desmoid
* Classical FAP: N-terminus * Attenuated FAP: C-terminus * Desmoid: middle
62
What is MYH Associated Polyposis? What makes it different from FAP?
* Hereditary colorectal cancer syndrome * Phenotype overlap w/ FAT * **20-100** adenomatous polyps * Autosomal recessive * Age at presentation \> FAP
63
What are the mutations for MYH Associated Polyposis?
* **1p34.3-p32.1** * MYH protein = DNA repair protein * Base excision repair * Removes oxidation-induced DNA damage * Removes A mis-paired w/ G * Two common mutations (85-90%) * **494A --\> G** * **1145G --\> A**
64

GI/Nutrition (36 decks)

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