1. Cellular Pathology of Cancer Flashcards
Define Metaplasia.
A reversible change in which one adult cell type (usually epithelial) is replaced by another adult cell type.
Describe Barrett’s Oesophagus. What type of metaplasia is this?
When gastro-oesophageal reflux causes the oesophageal epithelium to change from squamous to columnar.
This is pathological metaplasia.
Describe metaplasia in pregnancy.
In pregnancy, the cervix opens up and the columnar epithelium of the endocervical canal is exposed to the acidic uterine fluids making it become squamous
When the cervix closes up again, the cell types changes back to normal (hence why metaplasia is a REVERSIBLE change)
This is physiological metaplasia.
Define Dysplasia.
An abnormal pattern of growth in which some of the cellular and architectural features of malignancy are present.
The cells in dysplasia are on the road to cancer but haven’t reached it yet
Dysplasia is a pre-invasive stage with and intact basement membrane
What happens to the cells in dysplasia?
- There is a loss of architectural orientation
- There is a loss of uniformity of individual cells
- Nuclei are hyperchromatic and enlarged
- Mitotic figures are abundant, abnormal and in places where they aren’t usually found
What are common site of dysplasia? What are their causes?
- Cervix - HPV infection
- Bronchus - smoking
- Colon - ulcerative collitis
- Larynx - smoking
- Stomach - pernicious anaemia
- Oesophagus - acid reflux
Explain the picture.
This is a cervical biopsy
On the left you can see that the cells are very compact at the bottom then become more and more spaced out towards the lumen - normal cellular maturation
On the right hand side of this image, the cells are NOTundergoing normal maturation
There are compact cells with dark, dense nuclei on the surface - these cells are normally seen further down
Describe what is meant by low and high grade dysplasia.
Low Grade - low risk of progression to cancer and more likely to be reversible
High Grade - high risk of progression to cancer and less likely to be reversible
Difference between low grade and high grade: both show changes of dysplasia, but the changes are more severe in high grade dysplasia
The nuclei are bigger and the nucleo-cytoplasmic ratio is higher in high grade dysplasia
Define Neoplasia.
Any new growth, benign or malignant.
Define malignancy.
An abnormal, autonomous proliferation of cells, unresponsive to normal growth control mechanisms
Name characteristics of benign tumours.
- DO NOT INVADE and DO NOT METASTASISE
- Encapsulated - fibrous
- They have a compressed capsule around them
- Exception: fibroids (leiomyoma) in the uterus does NOT have a capsule
- Usually well differentiated
- They look like the tissues they come from
- Slowly growing
- Normal mitoses.
When can benign tumours be fatal?
- Are in a dangerous location - e.g. meninges, pituitary
- Secrete something dangerous - e.g. insulinoma
- Gets infected - e.g. bladder (whenever you block anything that drains fluid, you will create the conditions for infection)
- Bleeds - e.g. stomach
- Ruptures - e.g. liver adenoma (can cause massive haemoperitoneum)
- Torts (twisted) - e.g. ovarian cyst
Describe characteristics of malignant tumours.
- Invade surrounding tissues
- Spread to distant sites
- No capsule
- Well to poorly differentiated
- Rapidly growing
- Abnormal mitoses
Define metastasis.
A discontinuous growing colony of tumour cells at some distance from the primary cancer.
What does the site of metastasis depend on?
- The site of metastasis depends on the lymphatic and vascular drainage of the primary site
- Example: The pancreas is drained by the splenic vein, which then goes via the hepatic portal vein to the liver so pancreatic carcinomas tend to be present with liver metastases
- Lymph node involvement has a worse prognosis
Define papilloma.
A benign epithelial tumour of surface epithelium. E.g. skin, bladder
Define adenoma.
A benign epithelial tumour of glandular epithelium. E.g. stomach, thyroid, colon, kidney, pituitary, pancreas.
Define carcinoma.
A malignant tumour derived from epithelium
Name types of carcinomas.
- Squamous cell carcinoma
- Adenocarcinoma (adenoma that has become malignant)
- Transitional cell carcinoma (transitional epithilium is found in the bladder)
- Basal cell carcinoma
What are benign soft tissue tumours of:
- bone
- fat
- smooth muscle
- Bone = osteoma
- Fat = Lipoma
- Smooth Muscle = Leiomyoma
Define sarcoma.
A malignant tumour derived from connective tissue (mesenchymal) cells
What are sarcomas of the:
- fat
- bone
- cartilage
- striated muscle
- smooth muscle
- nerve sheath
called?
The prefix is the site of the tumour e.g. osteosarcoma (bone)
- Fat = liposarcoma
- Bone = osteosarcoma
- Cartilage = chondrosarcoma
- Striated muscle = rhabdomyosarcoma
- Smooth muscle = leiomyosarcoma
- Nerve sheath = Malignant Peripheral Nerve Sheath Tumour
Define Leukaemia.
Malignant tumour of bone marrow derived cells which circulate in the blood.
Define Lymphoma.
Malignant tumour of lymphocytes (usually) in lymph nodes - tissue based lesion.
NOTE: lymphocytes are produced by the bone marrow and the are found in lymph nodes so in some cases you can get a mix of both lymphoma and leukaemia
Define teratoma.
A tumour derived from germ cells which has the potential to develop into tumours of ALL THREE germ cell layers.
Three layers:
- Ectoderm
- Mesoderm
- Endoderm
Whats the difference between gonadal teratomas in men and women?
- Gonadal teratomas in males are almost ALL MALIGNANT
- Gonadal teratomas in females are MOSTLY BENIGN
Define Hamartoma.
Localised overgrowth of cells and tissue NATIVE TO THE ORGAN.
In other words: the tissues that are present are appropriate for that particular part of the body but the way that they are architecturally arranged is inappropriate
The cells are mature but architecturally abnormal
This is common in children, and should stop growing when they stop growing
Describe the picture.
- This is a section of the liver showing bile ducts
- A normal portal tract only contains ONE bile duct
- Here there are loads of bile ducts
- Normal bile ducts are round but these ones are a little misshapen
- Though there are no issues cytologically
- These bile ducts are abnormally arranged
How are tumours differentiated?
- Tumours are graded (how well differentiated they are) and staged (how far they’ve spread)
- Staging is more important
- High grade tumours generally have a high stage
- If you find a tumour you need to find out whether it is a primary tumour or if it is a secondary - this can be done by inspecting the tumour histologically and looking for evidence of normal function still present. E.g.
- keratin is made by squamous cells
- bile is made by hepatocytes
- hormones e.g. insulin is made by the pancreas
Define anaplastic tumours.
Tumours that show little or no differentiation.
What is the specific grading systems for:
- breast cancer
- prostate cancer
Breast - Nottingham scoring system
Prostate - Gleason classification
