Clinical Pathology: Intro to Cytology, Cytology of Effusions Flashcards

1
Q

What are the indications for cytology?

A

Characterise a detected abnormality-
mass/infiltrative lesion, organomegaly, ulcerative/exudative lesion, cavity or joint effusion

Staging of cancer- LN or internal organ metastasis

Diagnostic work-up of a patient with fever of unknown origin, hypercalcemia, monoclonal gammopathy

Bone marrow aspiration for investigation on non-regenerative anaemia, thrombocytopenia, bicytopenia, pancytopenia

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2
Q

What are the expectations for cytology?

A
  • Highly dependent on the quality of the sample submitted
  • Mostly the only option for fluids, the best option for BM and round cell tumours
  • Detect inflammation and suspect or detect infection
  • Detect neoplasia in most cases
  • Differentiate between benign and malignant lesions and identity tumour type in many cases
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3
Q

What are histology and cytology?

What are the pros and cons of each?

What are the limitations of cytology?

A

Histology- the study of disease through evaluations of tissue sections

Cytology- the study of disease through the evaluations of cells

Pros v Cons

Cytology- less invasive, less time, lower cost, in house, excellent cellular assessment, can assess fluids

Histology- can use immunostains, most representative and shows tissue architecture

Cytology limitations-
Sometimes difficult to achieve a final diagnosis on a cytology sample even for an experienced clinical pathologist as a tissue architecture cannot be assessed
It May not be representative or inadequate quality
We can look as slides straight away but may need external lab

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4
Q

What are the sources of cells usef for cytology?

How are cells collected?

A

Sources-
tissue- palpable lesion, internal organs, LN, BM
Fluids- body fluids- abdominal/thoracic effusions, joint fluid, cerebrospinal fluid, lavage and wash fluids
Body fluids/discharges

Collection-
Fine needle biopsy- sampling or aspiration
Touch imprints or scrapes
Swabs
Aspiration of body fluids- cavitary, synovial, bile, urine
Administration and collection of body fluids- tracheal was, BAL

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5
Q

How can a cytology sample be improved?

A

Increase cellular yield-
take several aspirates, several smears
stain one to determine if cellular/representitive
submit all slides

Increase diagnostic quality-
apply a light tough to prevent smashing of cells
too thin, too thick

Minimise haemodilution- be quick and use non-aspiration first

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6
Q

How are cytology slides prepared?

A

Depends on whats being sampled

Masses and organs- squash

Biopsies- imprint

Fluids- smear

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7
Q

How are cytology slides processed?

Describe the approach to the cytology slide

A

Can be stained in house for quick evaluation
Recommend for checking the quality/cellularity of the sample
For surgical emergencies

Approach-
be consistent- always use the same order
be thorough- scan the entire slide and all stained slides
don’t jump straight to high power

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8
Q

What should be assessed by the naked eye, low power and high and very high power?

A

Nakey eye- labelling, staining and distribution assessment

Low power- 4-10x
A quick scan for quality, cell preservation and distribution (chose the sweet spot)
Scan for the big stuff (larvae, fungi, eggs)
Preliminary identification of cell types and their arrangement
Assess background

Artefacts- ruptured cells, poorly stained, formalin, ultrasound gel

High power- 40x, 50x
more accurate identification of cell types
Inflammatory, tissue cells or matrix
Classify inflammation- the type to help determine the aetiology
Identify cell tissue- normal or abnormal

Very high power- further characterisation of nuclear-cytoplasmic detail
Better ID od microorganisms

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9
Q

What are the following types of inflammation?

A

A- Histiocytic

B- Pyogranulomatous

C- Eosinophilic

D- Lympho-plasmacytic

E- Neutrophilic (suppurative)

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10
Q

What are examples of cavitatory fluid?

What is their purpose of them?

What are they composed of?

A

Peritoneal, pleural and pericardial cavity fluids- lined by mesothelium

Contain scant serous fluid that facilitates movement

An ultrafiltrate of blood- low cellularity, low total protein

Small animals have too little fluid to be sampled

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11
Q

What does the volume of fluid in body cavities depend upon

What is an effusion?

A

Depends on the equilibrium between:

The hydrostatic pressure of blood
Oncotic pressure of blood
Permeability of vessels

Effusion-
Any accumulation of fluid in a body cavity, indicative of a pathological process

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12
Q

How are effusions analysed?

A

Gross appearance- colour, turbidity

Odour

Cell counts and total protein

Microscopic examination

Biochemistry depending on case

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13
Q

How are effusions classified?

What is transudate and exudate?

A

Classified based on protein, cell count and cytology
Transudate- effusions are usually caused by imbalances of hydrostatic and/or oncotic pressure
Exudate- effusion is usually caused by increased vascular permeability due to inflammation

Classified based on aetiology and composition-
Haemorrhagic, Chylous, Pseudochylous, Neoplastic

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14
Q

What are haemorrhagic effusions caused by?

A

Heavily blood stained

Caused by true cavity haemorrhage-
vessel disruption, bleeding tumour, coagulopathy, trauma, lung lobe torsion

The fluid does not clot, and supernatant often does not haemolyse
Microscropy- erythrophagocytosis, no platelets

Iatrogenic blood contamination-
Initially clear then bloody/vice-versa
Should form clot, supernatant clear, can see platelets

Splenic tap

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15
Q

How is abdominal haemorrhage investigated with cytology?

A

Coagulation profile/haematology

Ultrasound abdomen to check for masses

Look for neoplastic cells

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16
Q

What is chyle?

A

Chylomicron-rich lymph

Chylomicrons-

TG- rich lipoproteins absorbed from the intestine
Transport of dietary lipid
Enter lymphatics, then blood via thoracic duct
Big so make fluid opaque- milky

17
Q

How do chylous effusions appear?

What is the protein amount?

What is their cell count?

What causes them?

A

Milky fluid- white opaque

Protein often >25g/l

Cell count variable- cytology mainly lymphocytes but can be mixed, neutrophils increase with chronicity

Formed due to lymphatic drainage impairment of lymphatic leakage
Causes-
Heart disease
Trauma/surgery
Neoplasia
Idiopathic

Chyloabdomen- rare

18
Q

What is pseudochyle?

A

Looks similar grossly to chyle

Not high in triglycerides

White colour due to cell debris, protein and cholesterol

Uncommon

19
Q

How do (low protein) transudates appear?

How much protein is in them?

What cells are present?

What causes them?

A

Clear, colourless

Protein <25g/l

Cell count low- <1.5x10^9
Few, mainly monocytes and macrophages

Duse to decreased oncotic pressure to due to low serum protein
Causes-
Severe hypoalbuminaemia- protein-losing enteropathy/nephropathy, liver disease
Portal hypertension
Over hydration
Cardiac failure
Thrombi in major vessles

20
Q

What is modified transudate?

How does it appear?

How much protein?

What is the cytology?

What causes it?

A

Modified- more protein and cells than pure but less then exudate

Colourless to amber/pink- clear

Protein >25g/l cell count <5 x 10^9

Cytology- low cellularity, mixed populations of cells, more neutrophils than a transudate

Caused by increased hydrostatic pressure
Increased IV hydrostatic pressure in liver or lung
CHF
Thrombi or neoplasia
Non-exfoliating neoplasia
Lung lobe/splenic torsion
Occasionally FIP

21
Q

How do exudates appear and how are they characterised?

A

Turbid
Yellow/brown/bloody
High nucleated cell count
High protein
Mostly neutrophils- inflammation

Due to increased vessel permeability

Septic or non septic

22
Q

How do septic and non-septic exudates appear?

What causes septic and non-septic?

A

Septic- intracellular organisms (not always visible), absence of organisms does not rule out sepsis, often degenerate neutrophils
Non-septic- non-degenerate neutrophils, lower number of hypersegmented neutrophils and pyknotic cells

Causes of septic-
penetrating wound, foreign body, GI perforation, Haematogenous route
less commonly- gall bladder rupture, pancreatitis, rupture of pyo, abscess in liver

Causes of non-septic
Ruptured gall bladder/urinary bladder, necrotic tumour, pancreatitis, FIP

23
Q

How does FIP exudate differ?

What causes bile peritonitis?

How can a ruptured bladder be diagnosed?

A

FIP-
virus- vasculitis
yellow sticky fluid, high protein (froths), moderate cellularity
Globulin: albumin ratio A:G low in FIP (>0.8 not FIP)
Mainly neutrophils

Bile peritonitis-
ruptured gall bladder/duct- trauma/obstruction
Fluid often green ± secondary infection
Neutrophils, macrophages, bilirubin higher then plasma

Ruptured Bladder-
conc creatine > conc creatine plasma
starts as transudate- urine it irritant- becomes exudate

24
Q
A
25
Q

Why do neoplasms cause effusions?

What are the pitfalls?

A
  • Compression of blood vessels and lymphatics
  • Increased vessel permeability
  • Inflammation
  • Necrosis
  • Haemorrhage
  • Cell exfoliation
  • Lymphoma, adenocarcinoma, mesothelioma

Pitfalls-
mesothelial cells found in all effusions
Shed off pleura/peritoneum
Become reactive
Look like tumor cells

26
Q

How do reactive mesothelial cells of the pleura appear?

A

Eosinophilic fringe or brush border

May be multinucleated

May contain prominent multiple nucleoli or variable shapes or sizes

May phagocytose cells and particulate matter

27
Q

What are the indications for arthrocentesis?

A
  • Joint disease of unknown aetiology
  • Disease in multiple joints
  • Suspected infectious arthritis
  • Pyrexia of unknown origin
  • Monitoring therapeutic response
28
Q

How does synovial fluid normally appear and how can it vary?

A
  • Normal- pale yellow
  • Inflammation- yellow turbid
  • Haemarthrosis- uniformly bloody
  • Contamination- clear then bloody

Normal- clear, pale yellow, very viscous, hypocellular, protein background
Trauma- grossly red, low viscosity due to effusion, red cells, some neutrophils
Osteoarthritis- cellularity normal or mildly increased, predominantly mononuclear, can see osteoclasts
Inflammatory arthropathy- viscosity reduced, cellularity increased, increased cells- degen neutrophils,
Septic arthritis- usually monoarticular, penetrating wound, haematogenous spread, often we do not see bacteria

29
Q

How should synovial fluid sampled be handled?

A

Make smear immediately

Note viscocity

Collect into EDTA and sterile plain tube

Always send fresh smear with sample

30
Q

What further investigations can be done for transudate and modified transudate?

A

Transudate-
Biochem- plasma serum
Urinalysis
Imaging
Look for GI/Renal disease

Modified transudate-
Auscultation, echocardiography
Liver enzymes, bile acids
Drain and re-Xray (mass/tumour)