Session 6 - Role of the Laboratory in Diagnosis Flashcards
Why is it important that the laboratory gets the diagnosis of cancer right?
Cancer treatment can lead to radical treatment that can be curative, but also disfiguring and harmful
What is sent to the histopathologist?
Tissue - Excisional Specimen - Diagnostic Biopsy - Incisional - Needle core Cytology - Exfoliative - Fine needle aspiration
Give methods of collecting samples for cytology
Shed
- Sputum, Urine, Pleural and ascitic fluid
Scrape
Aspirate
What is wrong with collecting shedded cells in cytology in order to detect cancer?
Cells usually degenerate so cancer pick-up rate is low
What method of finding cancer cells for cytology is superior?
Intact and viable cells are retrieved so cancer pick-up rate higher
Outline the processing of tissue samples
I’m Claire, a second year Modern Languages and Politics student. I am running for Publicity Officer for the upcoming year, a position that I also held, and enjoyed, last year. I feel I would be suitable for this role because I already a year of experience which I will be able to use to improve upon this year’s publicity as I know what worked well last year and what did not work as well. If elected, there are a number of things I hope to achieve. Firstly, I want to increase the publicity done via the Friends of MSF Facebook and Twitter pages to advertise the society’s events. In addition, I am hoping to keep the Friends of MSF page on the Students’ Union website up to date. This includes creating events online - which will then be advertised on the Union homepage in the days leading up to the event - so that more people may be able to find out about and support the society, as well as publishing articles about recent and upcoming events to keep people up to date with what we are doing. Finally, I hope to be able to branch out to more students from other departments, such as my main department of Modern Languages, to increase awareness of both Médecins Sans Frontières and their work, and the activities and events put on by the society to support them. I hope you’ll consider me for Publicity Officer!
Thanks,
Claire :)
Thanks for that Claire. Now really actually outline the processing of tissue samples
- Macro description of tumour, appearance size, spread etc
- Tissue resected during cancer surgery is inked to demonstrate the excision margin when you look at it down the microscope
- Blocks taken of areas of interest (tissue blocks impregnated with wax to support tissue while 4um sections are cut
- These sections are mounted on a glass slide and stained
Outline the 5 steps in the diagnostic process of tissue sampling
Is there a lesion? Is it malignant? What sort of malignancy is it? How malignant is it? (Grade) How far has it spread? Is it all out?
What are two categories of changes you need to look for in diagnosis of histological malignancy?
Tissue changes
Cytological Changes
What are three tissue changes that demonstrate malignancy?
- Dysplasia
- Invasion
- Infiltrative margin
What are three cytological changes which demonstrate malignancy?
- Nuclear pleomorphism, size shape and staining
- Increase proliferation, numbers of mitotic figures
- Abnormal mitotic figures
What four things do you look at to determine what sort of malignancy you’re looking at?
Histogenic classification of tumours
Identify differentiation
Architectural arrangement
Cytological differentiation
Give give different thing syou look for in cytological differentiation
- Morphology – desmosomes, mucin, melanin
- Protein expression- Lymphocyte differentiation antigens
- Filaments, low or high molecular weight cytokeratins
- Specific protein products, thyroglobulin
- Enzyme production
How do you determine the grade of a tissue tumour?
Based on the degree of differentiation Look at - Proliferation (Mitotic counts) - Tubule formation - Pleomorphism
What is a sentinal lymph node biopsy?
Removal of first lymph node in draining site as tumour will reach here first
