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Flashcards in Pathology of the stomach Deck (64):
1

List inflammatory disorders of the stomach

Acute gastritis
Chronic gastritis
Rare causes of inflammation:
lymphocitic
eosinophilic
granulomatous

2

List some causes of acute gastritis

Irritant chemical injury
Severe burns
Shock
Severe trauma
Head injury

3

List causes of chronic gastritis

Autoimmune
Bacterial
Chemical

4

Which parts of the stomach is affected by autoimmune gastritis?

The fundus and the body (pangastritis)

5

What happens to the stomach in autoimmune gastritis?

There is atrophic gastritis and loss of parietal cells with achlorhydria (low or absent stomach acid production) and intrinsic factor deficiency.
There may be intestinal metaplasia.

6

What does the intrinsic factor deficiency cause?

A lack of vitamin B12 and pernicious anaemia

7

What antibodies are present in autoimmune gastritis?

Serum autoantibodies to gastric parietal cells and to intrinsic factor.
Those to parietal cells are common and nonspecific, whereas those to intrinsic factor are rare and more significant.

8

What is there an increased risk of in autoimmune gastritis?

Malignancy and SACDC (subacute combined degneration of spinal cord) due to B12 deficiency

9

What is a bacterial cause of chronic gastritis?

Helicobacter pylori - this is the most common cause of bacterial chronic gastritis

10

Where in the stomach does the H pylori inhabit?

In a niche between the epithelial cell surface and the mucous barrier

11

What does H pylori look like on gram stain?

Gram negative flagellate curvilinear rod

12

What is the response to H pylori in the stomach?

There is an early acute inflammatory response. If it is not cleared then a chronic active inflammation ensues.

13

Which inflammatory mediator is critical in the response to H pylori?

IL 8

14

Where else other than the stomach is H pylori found?

In the duodenum in areas of gastric metaplasia.

15

Where is the prevalence of H pylori highest?

In developing countries (80-90%) and much lower in developed countries (20-50%)

16

How and when is H pylori infection usually acquired?

In childhood, either by the faecal-oral route or oral-oral route.

17

What is the most likely explanation for why the incidence of H pylori increases with age?

Probably due to acquisition in childhood when hygiene was poorer - the cohort effect- rather than infection in adult life.

18

Which enzyme does H. pylori produce?

Urease

19

How does H pylori damage the epithelial cells in the stomach?

Through the release of enzymes and inducing apoptosis by binding to the class II MHC molecules. The production of urease enabled the conversion of urea to ammonium and chloride, which are directly cytotoxic.

20

What are the possible results of H pylori infection?

Antral gastritis (the usual effect)
Peptic ulcers (duodenal and gastric)
Gastric cancer

21

What are the effects of antral gastritis?

It is usually asymptomatic, but can sometimes cause dyspepsia.
Chronic antral gastritis causes hypergastrinaemia due to gastrin release from G cells.
The subsequent increase in acid output is usually asymptomatic, but can lead to duodenal ulceration.

22

What do lamina propria plasma cells produce in response to H pylori infection?

anti H.pylori antibodies

23

What does H. pylori increase the risk of?

Duodenal and gastric ulcers
Gastric carcinoma
Gastric lymphoma

24

What can cause chemical gastritis?

NSAIDs, corticosteroids, alcohol and bile reflux

25

What happens to the mucous and epithelial layers in chemical gastritis?

There is direct injury to the mucous layer by fat solvents.
There is marked epithelial regeneration, hyperplasia, congestion and a little inflammation.
There may be erosion or ulcers.

26

Describe the general pathology in acute gastritis.

Surface epithelial degeneration
Regenerative hyperplasia of pit-lining epithelium
Vasodilation/congestion
Neutrophil polymorph response

27

Describe the general pathology in chronic gastritis

Lymphocyte and plasma cell response
Glandular atrophy
Lamina propria fibrosis
Intestinal metaplasia

28

What is peptic ulceration?

A breach in the gastrointestinal mucosa as a result of acid and pepsin attack

29

What are the major sites of peptic ulcers?

The first part of the duodenum
The junction of the antral and body muscosa in the stomach
The distal oesophagus
Gastro-enterostomy site

30

What are the main aetiological factors for peptic ulcer disease?

Hyperacidity
Helicobacter gastritis
duodeno-gastric reflux
NSAIDs
smoking
genetic factors

31

Are ulcers acute or chronic?

They can be either

32

What are some complications of peptic ulcer disease?

Haemorrhage
Penetration of adjacent organs
Perforation
Anaemia
Obstruction due to fibrous strictures
Malignancy
Stenosis
Intractable pain

33

What causes acute ulcers?

They develop as part of an acute gastritis, as a complication of a severe stress response due to mucosal ischaemia or as a result of extreme hyperacidity
(e.g. in patients with gastrin-secreting tumours such as Zollinger-Ellison syndrome)

34

Describe the pathogenesis of peptic ulcers

A combination of several factors:
Accelerated gastric emptying
Slower than usual neutralisation of gastric juice in the duodenal bulb due to decreased biliary, pancreatic and duodenal secretion
Impaired mucosa defences
Hyperacidity in some cases
There is synergism of several factors.

35

What drug can cause impaired mucosa defences? How?

NSAIDs
These inhibit prostaglandin synthesis

36

What is the macroscopic appearance of a peptic ulcer?

They can be 2-10cm across
The edges are clear cut, and appear punched out.

37

Describe the microscopic appearance of a peptic ulcer

The base consists of necrotic tissue and polymorph exudate overlying inflamed granulation tissue which merges with mature fibrosis tissue
The musculars propria can be completely replaced by fibrous tissue. Arteries within this fibrous base often show extreme narrowing of their lumina by intimal proliferation.

38

How do the ulcers heal?

A combination of epithelial regeneration and progressive fibrosis
Shrinking of the fibrous tissue may lead to pyloric stenosis or central narrowing of the stomach with outflow obstruction (the hour glass deformity).

39

What types of gastric tumours are there?

Benign (polyps):
Hyperplastic polyps
Cystic fundic gland polyps

Malignant (tumours):
Carcinomas
Lymphomas
Gastrointestinal stromal tumours

40

What is a polyp?

A protuberant mass of tissue.
It can either be neoplastic or form as a result of excessive reparative or regenerative process.

41

What is the commonest form of gastric polyp?

A hyperplastic or regenerative polyp
It involves simple elongation of the gastric pits separated by fibrous tissue or mildly inflamed lamina propria.
They are generally found against a background of H pylori-associated gastritis in the gastric antrum.

42

What are cystic fundic gland polyps?

This is seen in the type of mucosa found in the body of the stomach.
The main feature is enlargement by cystic dilatation of the specialised oxyntic glands.

43

What is the most common type of gastric carcinoma?

Adenocarcinomas

44

What do many gastric carcinomas arise on the background of?

Chronic gastritis and intestinal metaplasia

45

When do gastric carcinomas tend to present?

When they are clinically advanced.

46

What must all gastric ulcers be considered as?

Potentially malignant

47

Describe the aetiology of gastric carcinomas

The incidence varies widely.
There is a high incidence in Japan, China, Columbia and Finland suggesting genetic factors.
The incidence is in decline worldwide.
Migrant studies suggest an environmental process.

48

Where in the stomach are adenocarcinomas most common in the UK?

Proximal tumours of the cardia/GOJ are increasing, and more distal ones are decreasing.

49

Describe the role of H pylori in gastric adenocarcinomas.

H. pylori infection runs parallel to the incidence of gastric cancer in the same populations.
patients with anti H. pylori antibodies have a higher risk of cancer.
H pylori is the major cause of chronic gastritis.

50

Describe the pathogenesis of gastric adenocarcinoma as is caused by H pylori.

H pylori infection --> Chronic gastritis --> Intestinal metaplasia/atrophy --> Dysplasia --> Carcinoma

51

What are risk factors for developing gastric carcinoma?

Smoking, obesity and previous gastric surgery for benign conditions.

52

Name some premalignant conditions that can lead to gastric carcinoma.

Pernicious anaemia
partial gastrectomy
HNPCC/ lynch syndrome
Menetrier's disease

53

What are the subtypes of adenocarcinoma?

Intestinal type carcinomas: show glandular or papillary structures, and often originate from areas with intestinal metaplasia.
Tend to have an expansile growth pattern with a well demarcated pushing border. (60-70%)

Diffuse-type carcinomas: consist of chains of poorly cohesive, single cells infiltrating the wall with a poorly demarcated invasive margin. These cancers are thought to derive from the neck of the gastric gland and cancer cells may have large amounts of intracytoplasimc mucus compressing the nucleus to form so called "signet ring" cells. (30-40%)

54

Does intestinal type or diffuse type carcinoma have a better prognosis?

Intestinal type has a slightly better prognosis. This is largely explained by the more advanced stage of diffuse-type carcinomas at the time of diagnosis.

55

What percentage of gastric carcinomas are mixed intestinal and diffuse type?

15%

56

How do gastric adenocarcinomas spread?

Locally: into other organs and into the peritoneal cavity and the ovaries (these are Krukenberg tumours)
Lymph nodes. Remember the classical involvement of left supraclavicular nodes (Virchow's node) in abdominal cancer, particularly gastric.
Haematogenous: to the liver

57

Apart from gastric adenocarcinomas, which other types of malignant tumours are there in the stomach?

Neuroendocrine tumours
Malignant stromal tumours
Lymphomas

58

What is the commonest site for gastrointestinal stromal tumours (GISTs)?

The stomach

59

Where do GISTs originate from in the stomach?

The interstitial cells of Cajal

60

How do patients with GISTs present?

Haemorrhage
Anaemia
Anorexia
Weight loss due to secondary ulceration

61

What to GISTs in the stomach look like on endoscopy?

The tumour protrudes into the lumen and often has a central deep ulcer crater.

62

What is the commonest site for primary lymphomas of the GI tract?

The stomach

63

What is the most common type of lymphoma in the stomach?

Non-hodgkins B cell type.

64

What are gastric lymphomas closely related to?

Prior H pylori infection

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