Côlon: pathologies tumorales Flashcards
What are the most common tumoural pathologies of the colon?
Benign → polyps (found in 1/4 - 1/3 of pts during colonoscopy)
Malignant → colonic adenocarcinoma, polyposes, HNPCC
Macroscopically, what are the two different forms of polyps?
Pédiculé → au bout d’une tige
Sessile → sans tige, aplati sur le muqueuse
Microscopically, what are the four different forms of polyps?
Adénomateux
Hyperplasique/festoné
Hamaromateux
Inflammatoire
What is a polype adénomateux?
Excroissance d’épithélium glandulaire dysplasique —> risque de transformation maligne (case of abnormal cell growth/replication)
What are the 3 sub-types of polypes adénomateux?
- Tubuleux (80% of cases)
- Tubulo-villeux
- Villeux
IF VILLEUX/TUBULO-VILLEUX… INCREASED RISK OF MALIGNANT TRANSFORMATION
What increases the risk of malignant transformation of polypes adénomateux?
- Type villeux
- Taille → bigger = growing for longer = more likely to transform
What is a polype hyperplasique/festonné?
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)
Info on festonné:
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)
What is a polype harmartomateux (juvénile)?
Stroma with hyper abundance of lamina propria and cystic glands
Usually only one
Typically found during childhood or with certain forms of polyposes
What is familial polyposis? (polypose)
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
What is a polype inflammatoire?
Muqueuse normale ou inflammée qui prolifère dans des états inflammatoires (MII)
Séquelles de colite
Pas de risque de transformation maligne
What are the clinical manifestations of polyps?
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
How are polyps treated?
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
Stats on malignant tumours:
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%
What are some FDRs? (3 categories)
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
What are the 5 important syndromes génétiques familiaux to know?
- Polypose familiale adénomateuse (FAP/PFA)
- Peutz-Jeghers
- Polypose familiale juvénile
- Polypose hyperplasique
- HNPCC → Lynch syndrome
What is polypose familiale adénomateuse (FAP/PFA)?
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)
What is a prophylactic colectomy?
Removal of part or the entire colon for the purposes of cancer prevention