L12 - Pathology of GI cancers Flashcards
GIST caused by…
GIST - gastrointestinal stromal tumour
Mutation in receptor tyrosine kinase, platelet derived growth factor receptor a.
Describe Menetrier disease?
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.
Describe Zollinger-Ellison syndrome
Gastrin secreting tumours that cause parietal cell hyperplasia and hypersecretion.
Fundus gland polyps be found in what types of patients…
PPI theraphy
Familial adenomatous polyposis patients
Barret Oesophagus
Intestinal metaplasia within the oesophageal squamous mucosa.
State two types of oeosophageal tumour
Adenocarcinoma
Squamous cell carcinoma
Describe adenocarcinoma in GI tract
- most arrise from Barret oesophagus
- tabacco, radiation
- progression from barret oesophagus to adenocarcinoma occurs over a long time
Describe squamous cell carcinoma in GI tract
- more common that adenocarcinoma
- radiation, alcohol, tobacco
- reccurrent abnormalities of transcription factor SOX 2
- dysphagia
- Odynophagia (pain on swallowing)
Describe FAP in patients
Autosomal dominant
Patient develops numerous colorectal adenoma as teenagers.
Caused by mutations in APC gene,
Wnt signalling
Group of signal transduction pathway.
Begins with protein that passes signal into a cell through cell surface receptor.
Define dysplasia
Disordered growth of epithelium.
Hasn’t invaded tissue yet.
May be flat, may be polyp.
State some architectural / cytological abnormalities that would be present in dysplasia
Pleomorphism - occurrence of more than one form of a natural object (lots of different shaped cells)
Hyperchromatic nuclei - darkened nuclei
Mitoses
Malignant neoplasma appearance
Locally invasive
Destructive growth that can metastasise.
Heterogeneous
Describe appearance of benign neoplasm
Localised well circumscribed, encapsulated, homogeneous cut surface
How may metastasis occur?
- Haematogenous spread - venous to liver / lungs
- Lymphatic spread - locoregional lymph nodes
- Seeding of body cavities - eg. peritoneal cavity
- Mechanical - needle biopsy tract (iatrogenic)
Iatrogenic
Medically caused.
e.g. giving a patient chemoradiotherapy
Describe the following terminology
Carcinoma Melanoma Lymphoma Sarcoma Germ cell tumour
Carcinoma (epithelium) Melanoma (melanocytes) - supporting connective tissue Lymphoma (lymphoid cells) - T cell & B cells Sarcoma (mesenchymal) Germ cell tumour
Normal oesophagus lined with…
Squamous epithelium
Malignancy - invasive squamous cell carcinoma
Squamous - white colour
Describe how Barrett’s oesophagus comes to be?
Prolonged reflux (GORD) - squamous epithelium replaced by glandular epithelium (columnar metaplasia)
Describe the lining of the stomach
Stomach is lined by glandular epithelium.
What are the two main types of gastric adenocarcinoma?
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)
Signet ring cells
Cell with an abnormally large vacuole.
Malignant type predominantly seen in carcinomas.
Frequently associated with stomach cancer.
Neuroendocrine tumours
Endocrine cell tumours
‘salt and pepper’ nuclear chromatin
Arise in stomach
Describe GIST tumours
Arise from mesenchymal cells
Can be spindle cell or epithelioid.
Describe Familial adenomatous polyposis
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
Describe tumour staging T1 T2 T3 T4
T1 - tumour invades submucosa
T2 - invasion of muscularis propia
T3 - invasion of subserosa
T4 - tumour perforates serosa or directly invades other organs or structures
Describe TMN classification of tumours
T - extent of primary tumour
N - lymph nodes involved or not
M - distant metastases
