Cytology of tumours Flashcards
List the 6 indications for cytology
- Lesion (nodule, mass, plaque) palpable externally or seen on imaging
- Organomegaly
- Cavitary effusion
- Cancer staging (lymph nodes, liver, spleen, BM)
- Pyrexia of Unknown Origin
- Test of choice for a bone marrow exam
What are the expectations of using cytology
- Identify inflammation
- Suspect or detect infection (with also preliminary morphologic identification)
- Detect neoplasia
- Differentiate between benign and malignant in most cases
- Identify cell of origin in many cases
Is specificity or sensitivity higher for cytology? What does this mean?
Sensitivity 75 – 89 %
Specificity 97 – 100%
- Therefore diagnosis of cancer are very likely to be true but need to be cautious if cancer is suspected but cytology non-confirmatory
- Results are often suggestive or supportive i.e. a guide to clinical decisions rather than a definitive answer
What questions should be asked when you are approaching examination of a cytology slide?
What is expected normally on the tissue/organ sampled?
1. Consider differentials for lesion
2. Adequate quality and cellularity?
3. Inflammation or neoplasia (or both?)
4. If inflammation, what type?
5. If neoplastic, what type?
6. Malignant or benign?
Describe staining of sample slides in house
Diff quik
Wear gloves
10 dips in each
Then rinse the slide
Describe the approach to the slide at 1x magnification (naked eye)
Is the slide labeled adequately?
Macroscopic appearance of sample
Staining? Distribution of material?
Describe the approach to the slide at 4-10x magnification
Scan all the slides and choose the most representative area of the slide
- Intact cells, thin region with good cytoplasmic/nuclear detail “sweet spot”
- Identify cell populations
What do ruptured cells on a sample indicate?
Incorrect sampling or smearing technique
Repeat applying less pressure
Use a needle-only technique
What does inadequate staining of a slide indicate?
Insufficient time
Inadequate drying prior to staining
Layer of cells too thick
Too close to histo pot… (formalin fumes exposure)
What is the predominant inflammatory cell seen in most cases?
Neutrophil
What other inflammatory cells may be seen?
Macrophages
Lymphocytes and plasma cells
Eosinophils
When using cytology for masses what kinds of cells might you see?
Epithelial cells - skin, gut, glandular
Mesenchymal - connective tissue, muscle
Round cells - mainly cells of the immune system
Which normal cells seen in inflammatory processes are often misinterpreted as malignant cells?
Reactive fibroblasts
If neoplasia is suspected from cytology, starting from low power how/what should you assess on the slide?
- Cell arrangement
- Cell shape
- Criteria of malignancy
- Cell types
What cell shapes might be seen?
Round
Polygonal
Spindle
Name the cell type seen in adenomas and carcinomas
Epithelial cells
How do epithelial cells appear on cytology
Cohesive - adhere to one another in clusters and clumps ‘islands of cells’
Well defined cell-cell junctions
Usually polygonal, cuboidal, columnar, round cells with round to oval nuclei
How do round cells appear on cytology
Non-adherent, individualized
‘Sea of round, discrete cells’
Usually round cells with round to oval nuclei
Size generally small relative to epithelial and spindle cells