L12 - Pathology of GI cancers

Question 1

GIST caused by…

Answer 1

GIST - gastrointestinal stromal tumour

Mutation in receptor tyrosine kinase, platelet derived growth factor receptor a.

Question 2

Describe Menetrier disease?

Answer 2

Massive overgrowth of mucous cells (foveola) in mucous membrane lining stomach, results in large gastric folds.

Due to:
- excessive secretion of TGF-A, diffuse foveolar hyperplasia and protein losing enteropathy.

Question 3

Describe Zollinger-Ellison syndrome

Answer 3

Gastrin secreting tumours that cause parietal cell hyperplasia and hypersecretion.

Question 4

Fundus gland polyps be found in what types of patients…

Answer 4

PPI theraphy

Familial adenomatous polyposis patients

Question 5

Barret Oesophagus

Answer 5

Intestinal metaplasia within the oesophageal squamous mucosa.

Question 6

State two types of oeosophageal tumour

Answer 6

Adenocarcinoma

Squamous cell carcinoma

Question 7

Describe adenocarcinoma in GI tract

Answer 7

• most arrise from Barret oesophagus
• tabacco, radiation
• progression from barret oesophagus to adenocarcinoma occurs over a long time

Question 8

Describe squamous cell carcinoma in GI tract

Answer 8

• more common that adenocarcinoma
• radiation, alcohol, tobacco
• reccurrent abnormalities of transcription factor SOX 2
• dysphagia
• Odynophagia (pain on swallowing)

Question 9

Describe FAP in patients

Answer 9

Autosomal dominant
Patient develops numerous colorectal adenoma as teenagers.

Caused by mutations in APC gene,

Question 10

Wnt signalling

Answer 10

Group of signal transduction pathway.

Begins with protein that passes signal into a cell through cell surface receptor.

Question 11

Define dysplasia

Answer 11

Disordered growth of epithelium.

Hasn’t invaded tissue yet.
May be flat, may be polyp.

Question 12

State some architectural / cytological abnormalities that would be present in dysplasia

Answer 12

Pleomorphism - occurrence of more than one form of a natural object (lots of different shaped cells)

Hyperchromatic nuclei - darkened nuclei

Mitoses

Question 13

Malignant neoplasma appearance

Answer 13

Locally invasive
Destructive growth that can metastasise.
Heterogeneous

Question 14

Describe appearance of benign neoplasm

Answer 14

Localised well circumscribed, encapsulated, homogeneous cut surface

Question 15

How may metastasis occur?

Answer 15

1. Haematogenous spread - venous to liver / lungs
2. Lymphatic spread - locoregional lymph nodes
3. Seeding of body cavities - eg. peritoneal cavity
4. Mechanical - needle biopsy tract (iatrogenic)

Question 16

Iatrogenic

Answer 16

Medically caused.

e.g. giving a patient chemoradiotherapy

Question 17

Describe the following terminology

Carcinoma 
Melanoma 
Lymphoma 
Sarcoma 
Germ cell tumour

Answer 17

Carcinoma (epithelium)
Melanoma (melanocytes)
- supporting connective tissue
Lymphoma (lymphoid cells) 
- T cell & B cells 
Sarcoma (mesenchymal)
Germ cell tumour

Question 18

Normal oesophagus lined with…

Answer 18

Squamous epithelium
Malignancy - invasive squamous cell carcinoma

Squamous - white colour

Question 19

Describe how Barrett’s oesophagus comes to be?

Answer 19

Prolonged reflux (GORD) 
- squamous epithelium replaced by glandular epithelium (columnar metaplasia)

Question 20

Describe the lining of the stomach

Answer 20

Stomach is lined by glandular epithelium.

Question 21

What are the two main types of gastric adenocarcinoma?

Answer 21

Intestinal type
- from dysplasia pathway
- forms glands  
Diffuse type 
- adenocarcinoma 
- consists of poorly cohesive malignant cells with little or no gland formation  (may have signet-ring cells)

Question 22

Signet ring cells

Answer 22

Cell with an abnormally large vacuole.
Malignant type predominantly seen in carcinomas.
Frequently associated with stomach cancer.

Question 23

Neuroendocrine tumours

Answer 23

Endocrine cell tumours
‘salt and pepper’ nuclear chromatin

Arise in stomach

Question 24

Describe GIST tumours

Answer 24

Arise from mesenchymal cells

Can be spindle cell or epithelioid.

Question 25

Describe Familial adenomatous polyposis

Answer 25

Autosomal dominant inheritance.
Deletion of one copy of APC gene (tumour suppressor gene) on 5q11

Patient may have 100s or 1000s of adenomata by age 20-30 y/o

Question 26

Describe tumour staging 
T1
T2
T3
T4

Answer 26

T1 - tumour invades submucosa
T2 - invasion of muscularis propia
T3 - invasion of subserosa
T4 - tumour perforates serosa or directly invades other organs or structures

Question 27

Describe TMN classification of tumours

Answer 27

T - extent of primary tumour
N - lymph nodes involved or not
M - distant metastases