1. Cellular pathology of cancer Flashcards
What is metaplasia?
A reversible change, in which one adult cell type (usually epithelial) is replaced by another adult cell type
What changes occur in gastric metaplasia?
Stratified squamous to simple columnar
What cells appear in intestinal metaplasia?
Goblet cells
What is pathological metaplasia and give an example
• Reversible, benign change due to chronic physical or chemical irritation
• Barrett’s oesophagus
- gastro-oesophageal reflux causes the oesophageal epithelium to change from squamous to columnar
What is physiological metaplasia and give an example?
• Reversible, benign change due to the surrounding environment
- Endocervical canal exposed to acidic uterine fluids during pregnancy, as the cervix opens up
- Columnar => squamous epithelium
- Changes back to normal when cervix closes up
What is dysplasia?
- Pre-invasive stage of cancer development, with intact basement membrane
- Abnormal pattern of growth in which some cellular and architectural features of malignancy are present
How does the nucleo-cytoplasmic ratio change in dysplasia?
- Increased
* Cell size is normal, but too much nucleus
Describe the nuclei and mitotic figures in dysplasia
- Hyperchromatic and enlarged nuclei
* Abundant and abnormal mitotic figures, in places they shouldn’t be
Where is dysplasia common and what causes it in these places?
- Cervix - HPV
- Bronchus - smoking
- Colon - ulcerative colitis
- Larynx - smoking
- Stomach - pernicious anaemia
- Oesophagus - acid reflux
How does smoking change the bronchus epithelium?
Pseudostratified columnar => squamous - dysplasia => cancer
In a cervical biopsy how can you tell if the cells are normal or potentially cancerous?
- Normally compact at the bottom and more spaced out towards the lumen - normal cellular maturation
- Abnormal cells don’t undergo normal maturation, so you get compact cells with dark, dense nuclei on the surface
What is low and high grade dysplasia?
- Low - unlikely to go onto cancer, more likely to be reversible
- High - more severe: darker, higher nucleo-cytoplasmic ratio, less likely to be reversible
What is malignancy?
An abnormal, autonomous proliferation of cells unresponsive to normal growth control mechanisms
What is a neoplasia?
Any new growth, benign or malignant
What is a tumour?
A swelling, generally without inflammation, caused by abnormal growth of a tissue e.g. nasal polyps
How are benign tumours different from malignant tumours?
- Do not metastasise
- Encapsulated (still can invade the basement membrane)
- Usually well differentiated
- Slow growing
- Normal mitoses
When can benign tumours be fatal?
Growing in a dangerous place
• Meninges => epilepsy
• Pituitary => secrete hormones
• Lateral ventricles => increased intracranial pressure
• Insulinoma => hypoglycaemic episodes
• Gets infected e.g. in bladder
• Bleeds e.g. stomach tumours
• Ruptures e.g. liver adenoma => haemoperitoneum
• Torts (twists) e.g. ovarian cyst => infarction
How are malignant tumours different to benign tumours?
- Invade surrounding tissues
- Spread to distant sites
- Have no capsule
- Well to poorly differentiated - hard to determine where it originated
- Rapidly growing
- Abnormal mitoses
What is a metastasis?
Discontinuous growing colony of tumour cells, at some distance from the primary cancer (can break off and embolise around the body)
Where else is a pancreatic carcinoma likely to cause metastasis?
- Liver
* Pancreas drained by the splenic vein => hepatic portal vein -> lover
Outline how colon cancer survival changes when lymph nodes are involved?
Dukes staging system
• Dukes A - confined to bowel wall (90% survival)
• Dukes C - lymph node involvement (30% survival)
What type of tumour is a carcinoma?
Malignant epithelial tumour
What type of tumour is a sarcoma?
Malignant tumour arising from cells of mesenchymal (connective tissue) origin - soft tissue tumour
What is a papilloma and adenoma?
Types of benign epithelial tumours
• Papilloma - surface epithelium e.g. skin, bladder
• Adenoma - glandular epithelium e.g. stomach, thyroid
Give 4 examples of different carcinomas?
1) Squamous cell carcinoma - from skin/oesophagus
2) Adenocarcinoma - from glandular epithelium
3) Transitional cell carcinoma - from transitional epithelium (stratified epithelium where the surface cells change shape when stretched) e.g. bladder)
4) Basal cell carcinoma
Give 5 examples of benign soft tissue tumours?
1) Osteoma - bone
2) Chondroma - cartilage
3) Lipoma - fat
4) Leiomyoma - smooth muscle
5) Rhabdomyoma - striated muscle
Give 6 examples of sarcomas?
1) Liposarcoma - fat
2) Osteosarcoma - bone
3) Chondrosarcoma - cartilage
4) Leiomyosarcoma - smooth muscle
5) Rhabdomyosarcoma - striated muscle
6) Malignant peripheral nerve sheath tumour
What is the difference between leukaemia and lymphoma?
- Leukaemia - malignant tumour of bone marrow derived cells which circulate in blood
- Lymphoma - malignant tumour of lymphocytes, in lymph nodes or spleen
Lymphocytes produce in bone marrow and found in lymph nodes, so can get a mix of both types
What is a teratoma and how are they different in males and females?
• Tumour derived from germ cells
• Have the potential to develop into tumours of all 3 germ cell layers:
- Ectoderm
- Mesoderm
- Endoderm
• Gonadal teratomas are almost always malignant in males
• Gonadal teratomas are almost always benign in females (contain hair and teeth)
What is a hamartoma?
- Localised overgrowth of cells and tissues native to the organ
- Cells are mature but architecturally abnormal - no cytological issue
- Common in children, and should stop growing when they stop growing
- Most are benign, but there is a risk of malignancy
e.g. bile duct hamartomas (lots of bile ducts instead of one) , bronchial hamartomas
How can you look for evidence of normal function for the following cells: • squamous cells • glandular epithelium • hepatocytes • pancreas
- Squamous cells - keratin production
- Glandular epithelium - mucin production
- Hepatocytes - bile production
- Pancreas - insulin production
What is an anaplastic tumour?
Tumours with little or no differentiation - lost morphological characteristics of mature cells and their orientation
How does TNM staging work?
- Stands for ‘Tumour, Node, Metastasis’
- Grade - describes degree of differentiation (high grade = poor differentiation)
- Stage - describes how far it has spread (high stage = greater spread)
- Stage is more important
Which of the following do well-differentiated tumours not have:
• small number of mitoses
• lack of nuclear pleomorphism
• high nuclear-cytoplasmic ratio
• relatively uniform nuclei
• close resemblance to corresponding normal tissue
Well differentiated tumours do not have a:
• high nuclear-cytoplasmic ratio
