Colorectal pathology

Question 1

what is a poly?

Answer 1

protrusion above the epithelial surface
type of tumour (swelling)
can be benign or malignant

Question 2

all polyps are adenomas, true or false?

Answer 2

false

Question 3

what are the 4 differential diagnoses of a colonic poly?

Answer 3

adenoma
serrated polyp
polypoid carcinoma
other
distinguished via histopathoogy

Question 4

what 3 types of polyp can you get macroscopically?

Answer 4

pedunculated (dangling)
sessile (spongey)
flat
type determines how they can be removed

Question 5

what can polyps look like macroscopically?

Answer 5

irregular surface

long stalk

Question 6

what are adenomas?

Answer 6

precursors to adenocarcinomas

benign

Question 7

what do polyps look like histopathologically ?

Answer 7

dysplastic epithelial lining

Question 8

what are adenomas of the colon?

Answer 8

benign tumours
not invasive
do not metastesise
dysplastic

Question 9

what is the adenoma - carcinoma sequence?

Answer 9

normal mucosa > adenoma (dysplastic) > adenocarcinoma (invasive)
genetic injury is involved

Question 10

why must al adenomas be removed?

Answer 10

as they are premalignant

done endoscopically or surgically

Question 11

why don’t all colorectal adenomas have the same molecular genetic origins?

Answer 11

separate pathway for inherited tumours

separate pathway for serrated adenomas

Question 12

what is the primary treatment for a diagnosis of adenocarcinoma in most cases?

Answer 12

surgery

colon/rectum is removed and sent to pathology for staging

Question 13

what does a colorectal cancer look like?

Answer 13

tightly packed
moderately differentiated
“dirty” necrosis pattern
can invade muscularis mucosa - blueish gands going down like raindrops

Question 14

what is dukes staging?

Answer 14

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%)

Question 15

do tumours in the proximal/distal bowel present differently?

Answer 15

yes

Question 16

where are most colorectal carcinomas?

Answer 16

75% left sided (rectum, sigmoid, descending)

25% right sided (caecum, ascending)

Question 17

how does left sided colorectal carcinoma present?

Answer 17

blood PR
altered bowel habits
obstruction

Question 18

how does right sided colorectal carcinoma present?

Answer 18

anaemia

weight loss

Question 19

colorectal carcinomas generally have a gross, varied appearance, true or false?

Answer 19

true

polypoid, structuring, ulcerating

Question 20

are most polyps benign or malignant?

Answer 20

benign

can go from benign to dysplastic adenoma to adenocarcinoma

Question 21

where are colorectal carcinomas likely to locally invade?

Answer 21

mesorectum
peritoneum
other organs

Question 22

where are colorectal carinomas likely to lymphatically spread to?

Answer 22

mesenteric nodes

Question 23

where are colorectal carcinomas likely to spread hematogenously?

Answer 23

liver

distant sites

Question 24

what are the 2 group of inherited cancer syndromes of the colon?

Answer 24

hereditary
- HNPCC (lynch syndrome?)
- <100 polyps
- present in 50s/60s
- non polyposis
familial
- adenomatous
- polyposis (FAP)
- present at 16
- >100 polyps

Question 25

Describe HNPCC

Answer 25

late onset
autosomal dominant
defect in DNA mismatch repair
right sided mucinous tumours
crohns like inflammatory response
associated with gastric endometrial carcinoma

Question 26

describe FAP

Answer 26

early onset
autosomal dominant
defect in tumour suppression (FAP gene)
Adenocarcinoma throughout colon
No specific inflammatory response
associated with desmoid tumours and thyroid carcinoma