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Flashcards in Pathology Deck (132)
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1

What is a polyp?

A protrusion above an epithelial surface

2

Classify the vast amount of polyps in the large bowel

Benign, epithelial and neoplastic

3

Differential diagnosis of a colonic polyp

Adenoma
Serrated polyp
Polypoid carcinoma
Other

4

Three macroscopic appearances of removed colonic polyps

Pedunculated
Sessile
Flat

5

Explain adenoma of the colon

Benign tumours of the colon. Not yet invasive, and do not metastasise. All dysplastic = must be removed

6

Adenoma-Carcinoma Sequence

Normal epithelium -> mutations to APC -> small adenoma -> further mutation e.g. k-ras -> large adenoma -> chromosomal mutations e.g. p53 -> Invasive adenocarcinoma

7

Why remove all adenomas?

They are premalignant

8

Removal of adenomas by...?

Endoscopy
Surgery

9

Primary treatment of Adenocarcinoma

Surgical removal of colon/rectum for staging

10

What kind of tumours are majorly found in the large bowel?

Malignant Adenocarcinomas

11

Colorectal Carcinoma - Dukes Staging

Dukes A = Confined by muscular propria
Dukes B = Through muscular propria
Dukes C = Metastatic to lymph nodes

12

Left Sided Colorectal Carcinoma

75%
P/R Bleeding
Altered Bowel Habit
Obstruction

13

Right Sided Colorectal Carcinoma

25%
Anaemia
Weight Loss

14

Colorectal carcinoma - Gross appearance

Varied =
Polypoid
Stricturing
Ulcerating

15

Colorectal carcinoma - Histopathological appearance

Typical adenocarcinoma

16

Colorectal carcinoma - Local invasion

Mesorectum, peritoneum, other organs

17

Colorectal carcinoma - Lymphatic spread

Mesenteric nodes

18

Colorectal carcinoma - Haematogenous spread

Liver, distant sites

19

Inherited Colorectal Carcinoma - HNPCC

Late onset (50/60s)

20

Inherited Colorectal Carcinoma - FAP

Early onset (teens)
>100 polyps
Mutation to FAP gene
Tumours throughout colon
Adenocarcinoma NOS
Desmoid tumours & thyroid carcinomas

21

Diverticular Disease - Histopathology

Out-pouchings of mucosa
These are at increased risk of bursting and releasing septic contents into the abdominal cavity

22

Diverticular Disease - Complications

Inflammation
Rupture
Abscess
Fistula
Massive Bleeding

23

Ischaemia of the Large Bowel - Endoscopic View

Diffusely ulcerated and erythematous mucosa

24

Ischaemia of the Large Bowel - Histopathology

Withering of crypts
Smudging of lamina propria
Fewer chronic inflammatory cells

25

Ischaemia of the Large Bowel - Aetiology

CVS disease, A Fib, Embolus, Atherosclerosis (usually IMA), Shock, Vasculitis

26

Ischaemia of the Large Bowel - Clinical Context

Elderly
Left sided
Segmental on endoscopy

27

Ischaemia of the Large Bowel - Complications

Massive Bleeding
Rupture
Stricture

28

Antibiotic-Induced "Pseudomembranous" Colitis - Endoscopic View and Gross Appearance

Speckled, spotted appearance
Patchy, yellow membranous exudate on mucosal surface

29

Antibiotic-Induced "Pseudomembranous" Colitis - Histopathology

Explosive fibrinopurulent exudate on surface (volcano lesions)

30

Antibiotic-Induced "Pseudomembranous" Colitis - Causes

Patients in broad spectrum of antibiotics - C Diff proliferates
Toxins A and B attack endothelium and epithelium, causing mini-infarcts along the membrane