FNS Flashcards
Define cytology
study of cell number & type in tissue mass or fluid accumulation, to investigate its cause (usually inflammatory or neoplastic)
Give examples of common cytological specimens
Fine needle samples
- Capillary action sample
- Aspirate
Touch imprints
Body fluids
Lavages
What are the different types of fine needling sampling?
FNCS (fine needle capillary sample):
- With no suction
– no syringe attached
- preferred
FNA (fine needle aspiration):
- With minimal suction
– cysts or failed FNCS
What is the purpose of diagnostic cytology?
Differentiation of inflammation from tissue growth
- (hyperplasia/neoplasia)
Differentiation of types of inflammation
Detect neoplasia
- Malignant vs benign
- Indicate type of neoplasm e.g. sarcoma vs carcinoma & possible specific neoplasm
Differentiation of different fluids
- exudates, transudates etc
What are the advantages of cytological sampling?
Quick
Safe
Inexpensive
Cells can often be safely retrieved from lesions near vulnerable structures in conscious animals, making anaesthesia & surgical biopsy unnecessary.
Sampling demands little equipment or skill
Results can be quickly available
What are the limitations of cytology?
False negatives & false positives in the detection of neoplasia
What are some causes of false negatives in cytology
Poor exfoliation of a neoplasm
Failure to sample tumour tissue
Extensive necrosis/inflammation present
What are some causes of false positives in cytology
Inflammatory dysplasia
- proliferative & atypical cellular change (e.g. in mesothelial cells) due to inflammation or irritation
- Can mimic neoplasia
What is often the next diagnostic procedure after cytology?
Histopathology
Provides information on tissue architecture, adequacy of excision, invasion etc
Compare FNS to biopsy
What are the main types of inflammatory lesions
Neutrophilic
- Non-degenerate vs Degenerate
- Septic vs no organism seen
Eosinophilic
Granulomatous
What are the main types of cystic lesions
Epidermal (squames)
Sialocoele (saliva)
Seroma (serum)
Haematoma (blood)
What are the main types of neoplastic lesions
Epithelial
Round
Mesenchymal
Benign vs malignant
Describe epithelial neoplastic cells
High yield, forms clusters (rafts/sheets), cuboidal/columnar
Describe spindle/mesenchymal neoplastic cells
Low yield, elongated cells, often single (but may be in sheets)
Describe round neoplastic cells
High yield, discrete round cells, not adherent
