cytology + histopathy Flashcards
what is cytology?
(1 mark)
the scientific study of cells, performed by a pathologist
what are the two main branches of cytology?
(2 marks)
- intervention cytology
- exfoliative cytology
when is cytology used?
(5 marks)
- identify neoplastic cells
- identofy disease involving a body cavity e.g. peritonitis, chylothorac
- identify inflammatory conditions
- allow identification of stage of reproduction, prior to mating
- highlight bacterial infection
RVN role in cytology?
(5 marks)
- derm work up
- breeding support
- wound management
- support and management of neoplasia
- veterinary support
what is exfoliative cytology?
(1 mark)
examination of cells collected from areas of the body that naturally ‘shed’ / that can be exfoliated from the surface of tissue
example of exfoliative cytology?
(6 marks)
- skin + mucous
- respiratory tract
- urine
- GI tract
- discharge
- gynaecological tract
sampling methods for exfoliative cytology?
(8 marks)
- urine sample
- vaginal swab
- bronchialveolar lavage
- impression smear
- ear swab
- wound swab
- skin scrape
- endoscopic GI tract scrape
what is intervention cytology?
(2 marks)
examination of cells collected by intervention
traumatic cytology
examples of intervention cytology?
(2 marks)
- fine needle aspiration to obtain cells from a mass
- fluid aspiration from body cavity e.g. pericardial fluid, pleural fluid, peritoneal fluid, synovial fluid.
sampling methods of intervention cytology?
(5 marks)
- fine needle aspirate
- aspiration of fluid from body cavity
- US guided fluid/aspiration
- spinal tap
- joint tap
3 cytology collection techniques that fall under schedule 3?
(3 marks)
- FNA
- impression smear
- swab collection and sample prep
what is fine needle aspiration?
(1 mark)
introduction of a fine bore needle into the skin to collect a sample of cells and/or fluid for cytology analysis
what happens if you perform FNA too deep / too superficially?
(2 marks)
- deep = collect cells from central core (dead and necrotic)
- superficial = may not get true diagnosis
what imaging modalities may be used to guide FNA sampling technique?
(3 marks)
- US guided
- CT guided
- endoscope guided
what may imaging modalities used for FNA guidance be used for?
(5 marks)
- neoplasia
- inflammatory mass
- abscess
- lymph node
- needle guided FNA
what sized needle is used for an FNA sample?
(1 mark)
‘fine’ needle (21-27G) used
why is a fine gauge needle selected for FNA?
(4 marks)
- reduce pain
- reduce risk of haemorrhage
- reduce tissue damage
- reduce risk of tumour seeding
where is the core of the area of interest usually?
(1 mark)
5/8 to 1 1/2 inch for palpable superficial mass
syringe size for FNA sample?
(2 mark)
sufficient to introduce neg pressure to draw cells into needle hub / collect sufficient amount of fluid
commonly use 2.5-5ml.
disadvantages of a larger syringe when FNA sampling?
(10-20ml)
(4 marks)
- diff to handle, syringe handles can be used to reduce this
- reduce accuracy
- result in blood vessel rupture
- useful if fluid aspiration expected
disadvantages of smaller syringe when FNA sampling?
(1-2.5ml)
(2 marks)
- not produce sufficient presure to draw cells into needle hub
- insuficient to aspirate fluid
infection control of FNA site?
(3 marks)
- area surgically prep to avoid introduction of microbials along needle tract
- hand surgically scrubbed and/or covered with sterile gloves
- equipment sterile and disposed of appropriately
how to prepare FNA sample slide?
(3 marks)
- transferred to slide quickly as degrades quickly
- make smears immediately
- take 3-4 slides and if poor yield experiences, increase bore size of needle
what are non-aspiration techniques used for?
(and what it is)
(3 marks)
= FNA without syringe
* used for sampling vascular masses (reduces blood contaminatioln)
* useful when sampling precise location e.g. thyroid gland
advantages of non-aspiration technique FNA?
(9 marks)
- core biospy effecgtvely obtained - cellular structure is better maintained (than FNA)
- patient less apprehensive during sampling as equip minimal, not visualised and tissue damage pain can be reduced
- quick and easy technique
- realiatively cheap
- minimal trauma
- relatively painless
- performed on concious patient
- identification of cells to inform plan for surgical removal
- performed by RVN under schedule 3
disadvantages of non-aspiration technique FNA?
(8 marks)
- cheaper than surgical biopsy, but less diagnostic
- cells collected only from area of sample
- blood contaminants affect results
- patient required to be relatively quiet and amendable to allow diagnostic samples to be obtained
- sedation or local GA may be requierd
- RVNs unable to sample when entry to body cavity is necessary
- not appropriate for areas with surface infection, due to risk of infection seeding along needle tract
- complications are rare, but seeding of tumour cells can occur
