Colorectal pathology Flashcards
what is a poly?
protrusion above the epithelial surface
type of tumour (swelling)
can be benign or malignant
all polyps are adenomas, true or false?
false
what are the 4 differential diagnoses of a colonic poly?
adenoma serrated polyp polypoid carcinoma other distinguished via histopathoogy
what 3 types of polyp can you get macroscopically?
pedunculated (dangling)
sessile (spongey)
flat
type determines how they can be removed
what can polyps look like macroscopically?
irregular surface
long stalk
what are adenomas?
precursors to adenocarcinomas
benign
what do polyps look like histopathologically ?
dysplastic epithelial lining
what are adenomas of the colon?
benign tumours
not invasive
do not metastesise
dysplastic
what is the adenoma - carcinoma sequence?
normal mucosa > adenoma (dysplastic) > adenocarcinoma (invasive)
genetic injury is involved
why must al adenomas be removed?
as they are premalignant
done endoscopically or surgically
why don’t all colorectal adenomas have the same molecular genetic origins?
separate pathway for inherited tumours
separate pathway for serrated adenomas
what is the primary treatment for a diagnosis of adenocarcinoma in most cases?
surgery
colon/rectum is removed and sent to pathology for staging
what does a colorectal cancer look like?
tightly packed
moderately differentiated
“dirty” necrosis pattern
can invade muscularis mucosa - blueish gands going down like raindrops
what is dukes staging?
staging of colorectal cancer that predicts prognosis
Dukes A = confined by muscularis propria = good prognosis (90+%)
Dukes B = through muscularis propria = moderate prognosis (70%)
Dukes C = metastatic to lymph nodes = bad prognosis (35%)
do tumours in the proximal/distal bowel present differently?
yes
where are most colorectal carcinomas?
75% left sided (rectum, sigmoid, descending)
25% right sided (caecum, ascending)
how does left sided colorectal carcinoma present?
blood PR
altered bowel habits
obstruction
how does right sided colorectal carcinoma present?
anaemia
weight loss
colorectal carcinomas generally have a gross, varied appearance, true or false?
true
polypoid, structuring, ulcerating
are most polyps benign or malignant?
benign
can go from benign to dysplastic adenoma to adenocarcinoma
where are colorectal carcinomas likely to locally invade?
mesorectum
peritoneum
other organs
where are colorectal carinomas likely to lymphatically spread to?
mesenteric nodes
where are colorectal carcinomas likely to spread hematogenously?
liver
distant sites
what are the 2 group of inherited cancer syndromes of the colon?
hereditary - HNPCC (lynch syndrome?) - <100 polyps - present in 50s/60s - non polyposis familial - adenomatous - polyposis (FAP) - present at 16 - >100 polyps
Describe HNPCC
late onset autosomal dominant defect in DNA mismatch repair right sided mucinous tumours crohns like inflammatory response associated with gastric endometrial carcinoma
describe FAP
early onset autosomal dominant defect in tumour suppression (FAP gene) Adenocarcinoma throughout colon No specific inflammatory response associated with desmoid tumours and thyroid carcinoma
