Cytology Flashcards
What are the advantages of cutology?
- quick, easy, inexpensive
- Non-invasive and minimal risk to patient
- used as a screening tool to determine what diagnostic procedures should be performed next
- useful in Dx or IDing disease process
What are the limitations of cytology?
- Reliant on sample quality (skill of collecter, smear quality, type of tissue [exfoliation], site of collection)
- Experience/ability of person examining sample and quality of microscope
- Lack of information about tissue architecture (histopath provides this)
- Dx challenges of cytology
How does histopath compare to cytology?
- more expensive procedure as sterile
- slower turnaround (48hrs)
- poor detail for round cell tumours (cytology better)
- tissue architecture visable, tumour grading, immunohistochemistry more available
What samples can be analysed by cytology?
> Aspiration or imprints - superficial masses - LN enlargement/metastitis - Organs and deep masses with US guidance > Fluids - body cavities (peritoneum, pleural space, pericardium) - Joints - Respiratory tract (TTW, BAL) - Cerebrospinal fluid
What are FNA/Bs used for?
solid/fluid filled masses
- biopsy = aspirate but no negative pressure applied [no need really]
- aspirate may be carried out only if biopsy not successful (ensure remove negative pressure on plunger before removing from mass or contents will be sucked into syringe)
- only fill needle part of syringe, if fluid reaches syringe will probably be blood stained
- necrotic centre masses = ensure wall is sampled as well as centre
What are the goals of smear preparation?
- Thin areas with good cell spread
- Minimise cell damage
- Minimise blood content
Which cells are most suceptable to rupture if excessive pressure is applied when making a smear?
Neoplastic cells AND lymphocytes
What are touch impression/imprints good for and how should they be made?
- Evaluating excised tissue or superficial lesions
- Imprints made BEFORE tissue placed in formalin to go to histopath
- Use fresh cut surface (cut sample in half if necessary)
- Blot until dry with paper towel
- Roll sample against slide
- Air dry and stain
What type of pot should fluid be collected in to prevent clots?
EDTA
What type of pot should bacteriology samples be placed in?
Sterile
What are the 4 levels of analysis of cytology?
- Sample quality - enough cells, good condition, spreading, representative of lesion, normal cells as well as abnormal expected?
- Inflammation v. neoplasia
- Inflammatory = Septic v. Non-septic
- Neoplasia = Round cell v. Epithelial v. Spindle cell
- Neoplasia = Benign v. malignant
How can inflammatory be distinguished from neoplasia changes?
Sample dominated by inflammatory cells (neutrophils/eosinophils/lymphocytes/macrophages)
or tissue cells (neoplasia)?
> If both are present, need experience as could be inflammation with 2* dysplasia or neoplasia with 2* inflammation
> biopsy required
How can septic v non-septic inflammation be distinguished?
> Septic: bacteria/organisms WITHIN neutrophils, if extracellular may be contaminant. degenerate neutrophils [lysed due to O* burst]
Non-septic: No bacteria, no degenerate neutrophils.
Outline degenerative changes in neutrophils
- Nuclear change
- Nucleus swells, loses lobulation and becomes paler (chromatin less condensed)
- 2* to release of bacterial toxins
- Degenerate neutrophils -> suspect septic cuases even if no bacteria seen
What changes are seen in NON-degenerate neutrophils at the end of their life?
Pyknosis
