tumour behaviour and spread

Question 1

metaplasia

Answer 1

replacement of one fully differentiated cell type by another.
substituted cells are less sensitive to a particular stress. e.g. mucus-secreting glandular epithelium is more likely to protect itself from acid injury than squamous epithelium

Question 2

metaplasia of the oesophagus

Answer 2

The distal oesophagus epithelium, which is normally squamous epithelium, is converted into epithelium showing an increase in goblet cells and mucus-secreting cells to protect itself from acid injury in chronic exposure.
In a Barrett oesophagus, there is an increased risk for developing cancer, in this case, a distal adenocarcinoma.

Question 3

metaplasia from glandular to squamous epithelium

Answer 3

• occurs in the mainstem bronchus epithelium when pseudostratified columnar epithelium of the mainstem bronchus develops squamous metaplasia in response to irritants in cigarette smoke. there’s an increased risk for developing squamous cancer of the mainstem bronchus

Question 4

dysplasia

Answer 4

disordered cell growth. may involve squamous, glandular or transitional epithelium.

Question 5

nuclear features of dysplasia

Answer 5

• increased mitotic activity; high mitotic count
• increased nuclear size and chromatin
• disorderly proliferation of cells with loss of cell maturation as cells progress to the surface

Question 6

pleomorphism

Answer 6

a term used to describe variability in the size, shape and staining of cells and/or their nuclei therefore cellular and nuclear pleomorphism is a characteristic of malignant neoplasms and dysplasia.

Question 7

carcinoma in situ

Answer 7

a group of abnormal cells that remain in the place where they first formed. they have not spread. these cells may become invasive/metastatic cancer and spread into nearby normal tissue. also called stage 0 disease.

Question 8

nuclear featured then compared to a normal cell

Answer 8

• nucleus is larger, has irregular borders, and has more chromatin (hyperchromatic).
• nucleolus is larger and has irregular borders.
• mitoses have normal and atypical mitotic spindles

Question 9

main routes of metastatic spread of malignant tumours

Answer 9

• clonal expansion of cells
• malignant cells to lose their cell-to-cell adhesion molecules (cadherins)
• tumour attaches to BM and degrades it using metalloproteinases.
• cell receptors to attach to fibronectin and other proteins in the ECM to break it down.
• malignant cells produce cytokines that stimulate locomotion, so that they can move through basement membranes and the intra and extracellular matrices.
• penetrate blood vessels (intravasation)) to enter circulation
• encounters host defences (cytotoxic T cells)- some destroyed.
• those that survive coated in fibrin and platelets- forming tumour emboli.
• ends in target organ, attached to blood vessel wall and repeats step 6 in reverse (extravasation)

Question 10

types of metastasis

Answer 10

some cancers dont metastasize- basal cell carcinoma (BCC) is an example- these cells invade a tissue but don’t metastasize.

• lymphatic spread (tumours of epithelial origin- carcinomas), move through regional nodes and dispense to capillaries to reach target organs. (before entering the systemic circulation)
• haematogenous spread- direct invasion of blood vessels without lymphatic spread (common in sarcomas)

Question 11

sites of deposition

Answer 11

• malignant cells entering portal vein go to liver.

- malignant cells in vena cava go to the lung

Question 12

Renal cell carcinomas RCCs

Answer 12

commonly invade the renal vein, where the tumour has potential for extending into vena cava and to the right side of heart. Also have lymphatic spread to regional lymph nodes

Question 13

Hepatocellular carcinomas HCCs

Answer 13

invade the portal and hepatic veins. tumour obstruction of either vein produces portal hypertension, splenomegaly, and ascites. also spread to regional lymph nodes

Question 14

seeding

Answer 14

malignant cells exfoliate from a serosal surface and implant and invade tissue in a body cavity (pleural, pericardial, peritoneal)- ovarian cancer is the best example with seeding to abdominal cavity and organs.

Peripherally located lung cancers (usually adenocarcinomas) commonly seed the parietal and visceral pleurae, causing malignant pleural effusions.

Question 15

metastasis in the bone

Answer 15

most common site is the vertebral column.
Batson paravertebral venous plexus is responsible for the predilection of bone metastases to this site.

Breast cancer is the most common cancer metastatic to bone; second most common is prostate cancer.

Osteoblastic and osteolytic metastases

In osteolytic you get pathologic fractures, and hypercalcaemia