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
What may confused for bacteria?
Stain precipitate
When are increased numbers of macrophages seen?
Granulomatous inflammation eg. Mycobacterium sp or FB
What is ^ neutrophils and macrophages called? When is this seen?
Pyogranulomatous seen with fungal infections or FB
How are round cell identified?
- Individual cells not clustered
- Small/medium round/oval cells eg. medium lymphocyte = 2x RBC
- Round/oval nuclei
- Well defined cell borders
- Good cell yield
- Seen better with cytology than histopath
Give 6 types of round cell tumour
- Lymphoma
- Plasmacytoma
- Histiocytoma
- Mast cell tumour
- Transmisable venereal tumour (TVT)
- Melanoma
How are epithelial cells identified?
- Sheets/rafts/clusters
- Large cell size
- Cell-to-cell junctions but good cell border
- oval/angular shape
- Nuclei round andcentral
- Cytoplasm often abundant
- Good cell yield
- eg. sebaceous, mammary, liver
How are mesenchymal cells identified?
- Individual cells OR clumps
- Small medium sized
- Spindle/fusiform/stellate
- Indistinct cell border but not joined like epithlium
- Elongated nucleus
- Poor exfoliation
- Matrix production -collagen/ostoid
What are the benign and malignant tumours of epithelial cells?
Benign: Adenoma
Malignant: Carcinoma
What are the benign and malignant tumours of mesenchymal cells?
Benign: Fibroma
Malignant: Fibrosarcoma
What are the benign and malignant tumours of round cells?
Lots of different specific tumours with distinct prognosis and pathology
- Mast cell tumour only specific type
How is malignancy assessed?
> uniformity vs. pleiomorphism [or dysplasia] - carcinoma, sarcoma (exception of Lymphoma where monotony indicates malignancy)
Cytoplasmic and nuclear [most reliable] features associated with malignant behaviour (3 criteria required to call tumour malignant):
- Anisocytosis (varied cell size)
- macrocytosis (large cell size)
- Cell overcrowding
- Anisokaryosis (varied nuclear size)
- Multinucleation +- odd numbers of nuclei
- Macrokaryosis (giant nuclei)
- High nuclear to cytoplasmic ratio (N:C) in large cells [ie. small amount of cytoplasm is bad]
- abnormal or ^ mitotic figures
- coarse chromatin
- nuclear moulding
- Within nucleus: MacronucleOLI, varying nucleolar shape and size
Give some common problems seen with sample prep
- Formalin fumes destroy blood smears and cytology
- Refridgerating glass slides -> condensation ruins smear
- Lack of fresh smears
- Flies
