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MD1 GI - EXAM 1 > Côlon: pathologies tumorales > Flashcards

Côlon: pathologies tumorales Flashcards

1
Q

What are the most common tumoural pathologies of the colon?

A

Benign → polyps (found in 1/4 - 1/3 of pts during colonoscopy)

Malignant → colonic adenocarcinoma, polyposes, HNPCC

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2
Q

Macroscopically, what are the two different forms of polyps?

A

Pédiculé → au bout d’une tige

Sessile → sans tige, aplati sur le muqueuse

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3
Q

Microscopically, what are the four different forms of polyps?

A

Adénomateux

Hyperplasique/festoné

Hamaromateux

Inflammatoire

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4
Q

What is a polype adénomateux?

A

Excroissance d’épithélium glandulaire dysplasique —> risque de transformation maligne (case of abnormal cell growth/replication)

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5
Q

What are the 3 sub-types of polypes adénomateux?

A
  1. Tubuleux (80% of cases)
  2. Tubulo-villeux
  3. Villeux

IF VILLEUX/TUBULO-VILLEUX… INCREASED RISK OF MALIGNANT TRANSFORMATION

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6
Q

What increases the risk of malignant transformation of polypes adénomateux?

A
  1. Type villeux
  2. Taille → bigger = growing for longer = more likely to transform
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7
Q

What is a polype hyperplasique/festonné?

A

Excroissance de l’épithélium colique normal

5-6 mm

Plus souvent dans colon distal → rectum et sigmoïde

Sans potentiel malin et pas de signification clinique (hyperplasique)

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8
Q

Info on festonné:

A

Polypes hyperplasiques typiques BUT can have dysplastic changes or éléments adénomateux (polype mixte)

Bigger size than normal hyperplasique (> 1cm)

Mostly found in the right colon (caecum, transverse)

Able to transform → malignant… therefore considered an adénomateux (fréquence de colonoscopie de dépistage à la même fréquence que adénomateux)

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9
Q

What is a polype harmartomateux (juvénile)?

A

Stroma with hyper abundance of lamina propria and cystic glands

Usually only one

Typically found during childhood or with certain forms of polyposes

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10
Q

What is familial polyposis? (polypose)

A

Familial polyposis (familial adenomatous polyposis (FAP)) a hereditary condition marked by multiple adenomatous polyps with high malignant potential, lining the intestinal mucosa, especially that of the colon

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11
Q

What is a polype inflammatoire?

A

Muqueuse normale ou inflammée qui prolifère dans des états inflammatoires (MII)

Séquelles de colite

Pas de risque de transformation maligne

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12
Q

What are the clinical manifestations of polyps?

A

Usually asymptomatic which is why screening is so important

but if the muqueuse has ulcers and is friable or the polyps are big (> 1cm)

  • Rectorragie du côlon gauche
  • Spoliation chronique —> anémie et RSOS (recherche de sang occulte dans les selles) côlon droit
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13
Q

How are polyps treated?

A

Because they’re able to transform into something malignant.. polypectomies are done during the colonoscopie using a “pince à biopsie” or an “anse diathermique (lasso) avec/sans cautérisation”

Sent to histology → followed up with screening colonoscopies depending on type of polyp

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14
Q

Stats on malignant tumours:

A

Very common → 5% of the population

Chances increase with age, male sec, white people more than black

FDR: acromégalie, diabétieque, autres syndromes métaboliques

Prognostic: 5 year survival → 63%

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15
Q

What are some FDRs? (3 categories)

A

Épidémiologiques: visceral obesity, tabaco, alcohol, red/charred meat

Seemingly protective factors: physical activity, high fiber diet, calcium

Prédisposants: polyposis, MII, ATCD personnels de polypes, ATCD familiaux de polypes/cancer

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16
Q

What are the 5 important syndromes génétiques familiaux to know?

A
  1. Polypose familiale adénomateuse (FAP/PFA)
  2. Peutz-Jeghers
  3. Polypose familiale juvénile
  4. Polypose hyperplasique
  5. HNPCC → Lynch syndrome
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17
Q

What is polypose familiale adénomateuse (FAP/PFA)?

A

Most frequent one → 1/5000 people, H=F

APC gene → autosomal dominant on chromosome 5

Leads to development of more than 100 colonic adenomas even during childhood

100% risk of cancer at 40 w/o surgery (screening starting in childhood with prophylactic colectomy when dx)

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18
Q

What is a prophylactic colectomy?

A

Removal of part or the entire colon for the purposes of cancer prevention

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19
Q

What are the two different forms of FAP?

A
  1. Gardner syndrome:
    • FAP with desmoid tumours (benign but very big) and osteomas
    • Bénéficie d’une colectomie avec iléostomie et de multiples résections tumorales desmoïdes
  2. Turcot syndrome:
    • FAP with CNS tumours (glioblastoma, medulloblastoma)
20
Q

How is FAP investigated?

A

Gastroduodénoscopie (OGD) → visualizes the upper part of the gastrointestinal tract down to the duodenum

Sigmoidoscopie q an dès 10-12 ans → colonoscopie courte du colon gauche seulement

21
Q

How is FAP treated?

A

Prophylactic proctocolectomy (rectum and colon)

Familial counselling with genetics doctor

It’s impossible to remove 100-1000s of polyps during colonoscopy so colectomy when polyps are present or transforming

22
Q

What is Peutz-Jeghers?

A

Hamartomateux polyps in the intestin grêle

Taches brunâtres a/n muqueuse buccale (E/P)

Risk of neoplasia → 90% at 40-50 years

Dx between 20-40 years old

23
Q

What gene causes Peutz-Jeghers?

A

STK11/LKB1 on chromosome 19

24
Q

Which cancers are associated with Peutz-Jeghers?

A

Stomach or pancreas → 40%

Breast → 50%

Ovarian → 10-20%

25
Q

What is polypose familiale juvénile?

A

Rare

Hamartomatous polyps

Incidence accrue de néoplasie malgré le caractère de polypes

26
Q

What is polypose hyperplasique?

A

Still quite new dx

Multiple big polypes festonnée (≥ 5) in the colon proximal

27
Q

What is HNPCC (Lynch syndrome)?

A

The most frequent of all the genetic anomalies leading to colon cancer

> 10 polyps

28
Q

What genes cause Lynch syndrome?

A

MLH-1 and MSH-2 which are normally implicated in repairing genetic anomalies

29
Q

What are the Amsterdam Criteria?

A

Used to dx HNPCC

Presence of colorectal cancer:

  • Younger than 50
  • 3 members of the same family → other “lynch cancers” counted too
  • 2 successive generations

Présence d’instabilité microsatellite en histopathologie

30
Q

Recommendations for “suivi” for HNPCC:

A

Colonoscopy every 2-3 years starting at 25

Surveillance de l’endomètre/ovaires, estomac, et voies urinaires (other lynch cancers)

31
Q

What are the two types of Lynch syndrome?

A
  1. Neo only in colon
  2. Neo in other organs (small intestine, uterus, ureter)
32
Q

Link between MII and colonic neoplasia: REVIEW

A

Acquired risk depending on:

  • Étendue de la colite (pancolite vs gauche)
  • Duration of colitis
  • Uncontrollable inflammation
  • Association with hepatic disease (CSP)

Typically many aggressive tumours

Screening strategy with “multiétagées” biopsies searching for dysplasia

33
Q

Histoire familiale et tumeurs coliques malignes:

A

80% of cases are sporadic

20% have family history

  • 5% have polyposis
  • 15% have unknown genetic factors → risk couples if cancer/polyps in 1st degree relative (parent)
34
Q

When is screening done according to personal history of polyps?

A

1-2 petits adénomes tubulaires → 5 years

3-10, polype > 1cm, éléments villeux/dysplasie de haut grade → 3 years

10 polypes → refer to genetics and redo colono in less than 3 months

35
Q

What is the physiopathology that leads to development of ADK?

A

adénome —> carcinome

  • progressive accumulation of mutations that affect many genes that regulate normal cell growth/multiplication
  • evolution over many years which shows the importance of screening to reduce the amount of cancer and chances of death
36
Q

Where are most colon cancers located?

A

30% → right colon

15% → transverse

5% → descending

25% → sigmoid

20% → rectum

37
Q

What is the difference between the clinical presentation of neoplasm in the proximal and distal colon?

A
38
Q

What is the TNM classification of colon cancer?

A

T: envahissement de la tumeur localement

N: envahissement des lymphatiques → ADP

M: envahissement veineux → métastases

  • Ganglions → stade 3, pas de ganglions → stades 0-2
  • Métastase = stade 4
39
Q

How is colon cancer dx?

A

Coloscopie: méthode la plus sensible et permet la confirmation par bx

Other radiological techniques: lavement baryté, colonoscopie virtuelle

40
Q

What is the bilan d’extension?

A

All done in one visit after finding cancer

TDM thoraco-abdo-pelvien

Dosage CEA (suivi oncologieque)

Cancer du rectum: echo/IRM pour voir si interaction pelvienne

41
Q

How is colon cancer tx? (4)

A

Treated according to stage (TNM)

  • Surgery if no metastasis
    • In situ: polypectomie
    • Otherwise, segmentary excision of colon including lymphatics
  • Chemotherapy:
    • Stage 1 → not required
    • Stage 2 → open for discussion
    • Stage 3 → if net advantageous (ADP+ —> métastases ganglionnaires)
    • Stage 4 → palliative treatment
  • Radiotherapy:
    • Pre-op for rectal cancer
  • What to do if hepatic metastasis:
    • If solitary or unilobaire → resection chirurgicale à l’occasion
42
Q

How to prevent colon cancer?

A

Séquence adénome —> ADK: 5-10 years

When?

Starting at 50 years old in general population

If ATCD fam +: 10 years before age dx in family member

  • What is considered ATDC fam?
    • Fam > 60 → NO
    • 2+ fam > 60 → YES
    • Close fam (sibling, parent, etc.) → YES
43
Q

How is screening done… what are the available options?

A
44
Q

What is a FIT test?

A

Fecal Immunochemical Test (FIT)

FIT detects blood (only coming from lower intestines) in your stool which can be a sign of pre-cancer

45
Q

What are the advantages of colonoscopies?

A

Excellente SE

Allows for polyp resection

46
Q

What are the disadvantages of colonoscopies?

A

Costly, long waiting list

Uncomfortable

Bleeding post polypectomy in 1-3% of cases

Risk of perforation: 1/1000

47
Q

What are some other forms of colonic tumours? (4)

A
  1. Lipomas
  2. GIST (stromal tumours)
  3. Carcinoid tumours
  4. Lymphoma

MD1 GI - EXAM 1 (15 decks)

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