Lower GI tumours Flashcards
What type of tumours occur in the small intestine?
Malignant:
- adenocarcinoma
- Non-Hodgkin’s lymphoma
- Carcinoid
Benign:
- Peutz-Jeghers syndrome
- Adenomas, Leiomyomas, Lipomas
- FAP
What are the symptoms of small intestine tumours?
Abdominal pain Diarrhoea Anorexia Anaemia Malabsorption
Where in the small intestine do adenocarcinomas most commonly occur?
In the duodenum
What are the risk factors of cancer of the small intestine?
Crohn's disease Coeliac disease Family history Poor lifestyle: smoking, alcohol, diet Radiation exposure
What cells does Non-Hodgkin’s lymphoma affect in the small intestine?
The lymphocytes: either B or T
What is the treatment for NHL and adenocarcinoma?
Surgical resection
Chemotherapy + Radiotherapy if needed
What is Peutz-Jeghers syndrome?
A genetic condition, autosomal dominant
Consists of:
- mucocutaneous pigmentation (hands, feet)
- hamartomatous benign GI polyps
Peutz-Jeghers syndrome causes GI polyps, where in the GI system do they most occur?
Small intestine
Why do you need to be concerned about Peutz-Jeghers syndrome?
The polyps can bleed or cause intussusception (telescoping)
Also they can become malignant
What is an:
- adenoma
- leiomyoma
- lipoma?
Adenoma: benign tumour formed of glandular structures in epithelial tissue
Leiomyoma: benign tumour formed of smooth muscle
Lipoma: benign tumour formed of fatty tissue
What are carcinoid tumours of the small intestine?
A type of neuroendocrine tumour
Malignant tumours of cells of the neuro and endocrine system
What cells do carcinoid s. intestine tumours arise from?
What’s the normal function of these cells?
How does the tumour affect these cells’ functions?
Enterochromaffin cells
They release serotonin
In the small intestine
Causes excess release of serotonin
Describe the function of healthy enterochromaffin cells?
They are found around the small intestine
When they sense food in the lumen they release serotonin which makes the gut contract around the food, pushing it down
When they detect an irritant in food they release more serotonin to make food move through even faster, this is what causes diarrhoea
What is carcinoid syndrome?
Symptoms caused by the over-secretion of serotonin caused by a carcinoid tumour
Carcinoid syndrome occurs in all patients with carcinoid tumours of the small intestine.
True or false?
False
It only occurs if they have liver metastases
In about 5% of patients
Why does carcinoid syndrome occur?
It occurs when the liver loses the ability to metabolise the excess serotonin
So the serotonin builds up and causes symptoms
What are the clinical features of carcinoid syndrome?
Flushing
Wheezing
Diarrhoea
Abdominal pain
Right heart valvular fibrosis: tricuspid, pulmonary valves
Stenosis + regurgitation
Investigations of carcinoid syndrome?
Urine sample: you will see high levels of 5-HIAA which is the breakdown product of serotonin
USS: will show liver metastases
Management of carcinoid syndrome?
Somatostatin analogues: octreotide
Reducing tumour mass surgically
Chemotherapy
What tumours occur in the colon + rectum?
Adenocarcinoma Squamous cell carcinoma Carcinoid tumours Sarcoma Non-Hodgkin Lymphoma
Which is the most common colorectal cancer?
Adenocarcinoma
What are the risk factors for colon cancer?
Familial colon cancer disorders
Family history of colorectal cancer IBD: Crohn's + UC Diet: low fibre, lots of red meats Alcohol Smoking
What is sarcoma?
Cancer of connective tissue: in the colon they are usually leiomyosarcomas: smooth muscle tumour
What are the familial colon cancer disorders?
FAP: Familial Adenomatous Polyposis
HNPCC: Hereditary Non-polyposis Colorectal Cancer
