6.1 - Diagostic Cytology Flashcards
(37 cards)
Define diagnostic cytology
Interpretation of cellular changes related to benign, inflammatory and neoplastic conditions
Assessment of single cells or cell aggregates without typical landmarks seen in histopathology
Role in diagnosis in cytopathology
Screening investigation: populations at potential or real risk
Diagnostic investigation: symptomatic patients
: things to look for in diagnosis
Exfoliative cells in spaces (samples such as:)
- fluids - csf, urine
- secretions - sputum
Abrasive
- scraping - bronchus
Fine needle aspiration
- superficial: thyroid, breast, skin
- deep: lung, pancreas, liver
Changes in collection systems
- before: collection via glass bottles
- now: collection via plastic bottles - able to comment on macroscopic appearance (clarity, viscosity)
Which smear type is most common?
Squash
Advantage of plasma thrombin - CB collection method
Cheap
Requires plasma and thrombin only
Describe clot and scrape method - CB collection methods
FNA material aspirated onto slide
Material allowed to clot
Inserted into cassette for paraffin embedding
BBC cell block fixative
Needle rinsed in sample
In 1ml of BBC cyto-cell block fixative
Drain excess on filter paper
Scrap components
Shandon cytoblock method
Manual preparation, concentrate cells on shandon cytocentrifuge, transfer into NBF
Collodion bag method: summarise the method
- Test tube filled with collodion
- Collodion sets for 1 hr
- Excess collodion into a container
- Test tube is dried, filled with water
- Stored with paraffin cover into a fridge
- Add concentration formalin-fixed specimen into collodion-coated tube
- Centrifuge and remove supernatant
- Bag is clamped, wrapped in lens paper & transferred to cassette to process
Advantages of CB
- Maintain architecture to closely resemble surgical specimen
- Small tissue fragments appear as mini biopsies useful for:
- pattern recognition
- sub classification
- ID of features
- diagnosis - Stored indefinitely for future diagnosis + research purposes
Adv + Disad of: Clot and Scrape Method
Adv: inexpensive, no additional equipment required
Disadv: Does not work well with small samples, crush artifact is common
Adv + Disadv Formalin or alcohol vapour method
Adv: Cheap
Disadv: Time intensive, variable quality
Adv + Disadv: BBC fixative method
Adv: fast, low cost, good results
Disadv: none
Adv + Disadv: CB pellet alcohol fixation
Adv: inexpensive, rapid, good for FNAs of any types + fluids
Disadv: Cellular yield variable. limited data on IHC
Adv + Disadv: CB pellet formalin fixation
Adv: inexpensive, easy + rapid, optimal results for IHC and molecular studies
Disadv: Cellular yield variable
Adv + Disadv: Collodion method
Adv: Good cellular yield, good for samples with scant cellularity
Disadv: time consuming, toxic ether fumes
Disadvantage of plasma + thrombin method
- unable to control clot formation
- thrombo-plastin agents may interfere with surface antigens
- makes target for IHC challenging
Describe the process of plasma thrombin method
- cell suspension centrifuged
- supernatant aspirated and cell deposit mixed with plasma
- thrombin added and mixed
- Clot formed given time to retract
- Add NBF to clot
- Transfer clot to NBF for processing and sectioning
Applications for fine needle aspirations
- patients presented with a lesion
- ovarian cyst fluids: dermoid cysts
- collection of CSF: needle inserted at L3-L4
Applications of endoscopic ultrasound
- pancreatic lesions
- common bile duct lesions
Outline the what is done during cytopreparation
- review methods and safe handling of hazardous samples
- prep cell samples for microscopy from gynae + non-gynae samples
- recognise unsatisfactory samples, artefacts
- Understand the application of special techniques (IHC, PCE, FCM)
Fixative agents used
- alcohol
- 95% ethanol
- Acetic alc: 3% acetic acid + 95% ethanol
- Spray fixatives: isopropanol + water soluble wax - Post fix air dried smears in methanol
Purpose of differential stains
allows for easy distinction between cells based on pH of cytoplasm
