Notes

histogenesis

-epithelial - papilloma (benign), cacinoma (malignant)
connective tissue - lipoma, chondroma, leiomyoma (benign), sarcoma (malignant)
lymphoid - lymphoma
heamooietic - leukaemia

benign vs malignant
- benign - remain localised
slow grow
circumscribed often encapsulated
compresses normal tissue
produced by pressure on vessels tubes, nerves, organs and by excess production of substances e.g hormones

- malignant
infiltrative no capsule metastasies
rapid growth
loses resemblance to tissue of oringin

morphology , immunohistochemistry, molecular studies
normal - large cytoplasm, single nucleus, single nucleolus, fine chromatin
cancer- small cytoplasm, multiple nuclei and nucleoli, coarse chromatin

is the tissue normal?m, why not? is there a tumour? benign or malignant?
form of diffeeentiation does the tumour show?
histogenesis and differentiation - whats the difference?

histogenesis - formation of different tissues from undifferentiated cells in germ layers during development

cellular differentation - process by which a less specialised cell becomes a more specialised cell type
cell will differentiate into their full specilised type during histogenesis, tumours may not resemble the tissue of their origin (histogenesis) as they can re-differentiate

immunohistochemistry- immunohistochemistry

antibody, antibody, coloured label - colour change
looking for a specific antigen
some antibodies stain membranes of cells, some cytoplasm , some nuclear
always use a negative control- see where there is no staining
molecular techniques- FISH, in situ hybridization, PCR, ect

grading and staging of tumours
- grading is about how the cancer cells look under the microscope compared with normal cells
staging - structured assessment of disease extent - prognosis, operability
diagnose on the best differentiated areas
grade on worst differentiated

three tier
- well differentiated
- moderately differentiated
-poorly differentiated
resemblance to normal tissue
mitotic activity
pleomorphism