Lecture 24; Tumours of the colon Flashcards
What are the benign and malignant cancer of the bowel?
Benign tumours; Mostly polyps
Malignant tumours; Mainly adenocarcinomas
What is a polyp?
A circumscribed growth or tumour which projects above the surrounding mucosae
How is the nature of polyps determined? and what can it be?
Biopsy
Non neoplastic polyp
or
Neoplastic polyps - adenomas
What are the potential non-neoplastic polyps;
Hyperplastic polyps
Inflammatory polyps
Write some notes on hyperplastic polyps;
Benign (non-neoplastic)
Usually asymptomatic
Do NOT have malignant potential
3-6mm, common
Write some notes on inflammatory polyps;
Seen in IBD, overgrowth
Theyre benign, psuedopolyps
What are neoplastic polyps-adenomas? and some notes on presenting population
Adenomas, epithelial proliferation with variable degrees of dysplasia
- Benign polyps WITH malignant potential
- Mostly 50+
- Familial predisposition
What is the pathology of neoplastic polyps- Adenomas?
3 Main types;
Tubular adenomas - Most common, tubular glands Villous adenomas - Villous projections Tubulovillous adenomas - Mixture of above
Whats the clinical presentation of neoplastic polyps-adenomas?
Most asymptomatic, found co-incidentally
May bleed, or produce mucosal discharge
IF larger;
- Altered bowel habit
- Obstruction
Describe the adenoma to carcinoma sequence;
Benign - Hyper-proliferation = Adenoma polyp (small->large with growth) - Severe dysplasia (pre-cancerous, abnormal growth and metabolism)
Malignant
- Severe dysplasia can become adenocarcinoma
- Then can become invasive (cancer)
Look at slide 18 if confused
What is the main risk for neoplastic polyps?
Main risk is size of polyps
What is the progression of growth from hyperproliferative patch to malignant cancer associated with?
Changes in morphology and aquisition of many mutations (lots of genetic changes and expressive changes along the way)
Where can colorectal cancer occur?
Between the ceacum and the rectum
Write some notes on colorectal presentation;
Peaks between 60-70
If young case, then considered familial
Males more likely for rectal cancer
Whats the pathology of colorectal cancer?
- Adenocarcinoma
- Variable differentiation
Extra note for fun; can have central necrotic area as it can outgrow blood supply)
What is used for the staging of colorectal cancer?
TNM system
T = Extent of invasion in bowel wall (Thickness) N = Number of lymph nodes involved (Number) M = Metastatic disease present or not (Metastasis)
Prognosis determined by stage of tumour and tailors treatment plans
T1-4
What are the clinical features of colorectal cancer?
Abdo pain, mucous discharge, PR bleeding, change in bowel habit, bowel obstruction
RHS = iron deficiency due to occult bleeding (cant see / unoticed)
Spread to regional nodes….
Consitutional symptoms = weight loss, malaise
Think about locations and implications
What is familial polypois syndrome? inheritance pattern?
Group of inherited polypois syndromes
- Autosomal dominant
Predispotion to malignant transformations (adenomas) in colon etc
What is familial adenomatous polyposis?
Multiple adenomas in colon and elsewhere of gut - Most tubular adenomas
Heaps and heaps of polyps. Predisposed to malignant transformations.
Write some notes on familial adenomatous polyposis;
- Usually evident in adolescence
- LOTS OF POLYPS
- Transforms into cancer
- Autosomal dominant
- Prophylatic colectomy
Write some notes on hereditary nonpolyposis colorectal cancer? (HNPCC)
- Autosomal dominant inheritance
- Progress adenoma to carcinoma but no increase in polyps
- Due to inherited mutation in DNA mismatch repair gene
Regular screening and polyp removed.
What are the two types of familial colorectal cancer?
1) Familial adenomatous polyposis (A polyposis syndrome)
2) Hereditary nonpolyposis colorectal cancer
