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clinical pathology > Lecture 7 > Flashcards

Lecture 7 Flashcards

cytology

1
Q

common indications for cytology

A

subcutaneous, cutaneous masses, lymphadenopathy, pleural effusions, abdominal effusions, joint effusions, cutaneous lesions, discharges,

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2
Q

care when aspirating masses

A

if carcinoma –> risk of spreading tumour

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3
Q

advantages of cytology

A

samples collected quickly/easily, minimal sedation, inexpensive, rapid diagnosis

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4
Q

disadvantage of cytology

A

not always definitive diagnosis, good indication of type yof lesion, less good for evaluating malignancy potential, lesions do not exfoliate well,

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5
Q

methods for obtaining cytology samples

A

FNA, impression smears/swab smears for superficial lesions, biopsy (squash preparation), fluid smear, fluid cytospin preparation, scrapings for mites

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6
Q

cytology of solid lesions what to do

A

FNA, if ulcerated impression smear, if biopsy squash preparation, if more diffuse –> scraping

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7
Q

FNA procedure

A

2 slides, wipe to remove glass particles, needles (not too small: 21g), 5ml syringe, prep/clean skin +/- clip area, immobilise mass, insert tip of needle, retract plunger, advance needle and retract under the skin, release plunger to stop suction, withdraw needle, draw air into syringe, reattach needle,

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8
Q

when and what is aspiration/suction preferred?

A

very solid lesions –> with suction, for softer (lymph nodes, spleen, liver) lesions –> no aspiration, for internal lesions (lymph nodes) –> aspiration: sometimes worth trying both

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9
Q

needle only method, when?

A

vascular masses like spleen and liver, plus lymph nodes,

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10
Q

advantage of needle only method

A

reduces blood contamination

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11
Q

continuous suction method –> when

A

solid tumours, spindle cell tumour but if mass is vascular –> blood contamination

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12
Q

intermittent suction method

A

internal masses, when needle cannot be moved easily, release suction before withdrawing needle

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13
Q

aspirating lymph nodes and masses technique

A

sample min 2 lymph node, avoid mandibular lymph nodes –> old animals have larger lymph nodes (older have some degree of dental disease), avoid aspirating centre that might be necrotic

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14
Q

aspirating internal organs

A

before liver and spleen –> check platelet count to avoid causing iatrogenic haemorrhage, adrenal masses –> phaeochromocytoma (adrenaline causing tumour –> may cause release of adrenaline), splenic masses –> haemangiosarcoma (vascular tumour, suggested on imaging if mass is cavitated + low cytological yield), suspect

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15
Q

aspirating suspected carcinoma?

A

risk of tumour seeding, esp prostate or bladder

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16
Q

aspirating thoracic masses?

A

risk of pneumothorax, masses within mediastiunum of close to body wall may be suitable under ultrasound guidance

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17
Q

making the smear

A

want to spread cells to do monolayer

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18
Q

things to avoid when making the smear

A

too much on slide, compressing too much

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19
Q

solid lesions other evaluation

A

surface impression smear

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20
Q

problem with srface impression smear

A

lesion underlying may not exfoliate –> might get bacteria and inflammatory cells but nothing else

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21
Q

what to do with surface impression smear before putting it on the slide

A

blot it to remove blood

22
Q

squash preparation when?

A

small biopsy, often quite thick smears –> cant’ really see –> need to evaluate cells around the edge, good to assess if there are inflammatory cells, but value actually quite low

23
Q

scrapings, when?

A

visualisation of infectious agents within the skin, Demodex, Cryptococcus parasites

24
Q

handling of fluid samples

A

place fluid within EDTA AND plain tube –> EDTA for cytology, plain tube for culture (EDTA is bacteriostatic), store it in fridge

25
Q

what if fluid is very turbid/clear

A

can make direct smear or concentrate cells –> centrifuge or manually stir to force sedimentation, buffy coat preparation for diluted samples

26
Q

when should smear from fluid be done

A

ASAP

27
Q

centrifugation technique of fluid samples

A

low spin (1000rpm for 5-10 min), remove supernatant,

28
Q

diff quick staining advantage and disadvantage

A

rapid and cheap, BUT doesn’t always stain mass cell granules for mass cell tumours

29
Q

diff quick staining technique

A

air dry, fixation of methanol solution (clear or pale blue), minimum of 6 1 second dips, fixation in solution 1 (orange) min of 6 dips, fixation in solution 2 (dark blue) 6 dips depending on how thick the smear is (better to understain initially) –> rinse, dry

30
Q

diif quick staining –> different stain pots, why?

A

dirty one and clean one (skin vs ear cytology)

31
Q

what can cytology tell us?

A

cells within the smear –> inflammatory of non-inflammatory lesion?

32
Q

what if inflammatory cells?

A

neutrophils –> infectious / other –> non-infectious

33
Q

what if non-inflammatory cells?

A

malignant neoplastic/ benign neoplastic. hyperplastic/…

34
Q

naked eye examination of smear

A

look for blue bits –> focus on those

35
Q

low power smear examination

A

cell types across the slide, areas with different cells types, high cellular areas

36
Q

high power smear examination first preparatory steps

A

50x or 100x, cells? intact cells? are the cells spread out adequately? are the cells stained adequately?

37
Q

higher power smear examination –> evaluation of the slide step 1

A

are there lots of erythrocytes? –> contamination or true haemorrhage? some neutrophils may be from blood,

38
Q

higher power smear examination –> step 2

A

inflammatory cells present? what type? if neutrophils, degenerative changes? intracellular bacteria? infectious agents? if phagocytose within smear –> true infectious agents

39
Q

higher power smear examination –> step 3

A

degenerative neutrophils seen within tissues (not within blood), neutrophils with intracellular bacteria –> bacterial infection diagnosis whereas if bacteria outside –> bacteria may be from surface agents

40
Q

higher power smear examniation –> mixed inflammation

A

neutrophils, eosinophils, macrophages, lymphocytes

41
Q

higher power smear examination –> if no inflammatory lesion

A

round cells, epithelial, mesenchymal –> distribution, shape, nuclie, clarity, degree of exfoliation

42
Q

round cells characteristics on the slide

A

individualised (IMPORTANT), distinct cytoplasmic borders, often readily exfoliate, round or ovoid shaped nucleus

43
Q

main types of round cells in cytology

A

mast cells, plasma cells, lymphocytes, histiocytes

44
Q

epithelial cells characteristics on the slide

A

clusters (IMPORTANT POINT), tight or 3D structures, distinct cytoplasmic borders, variable exfoliation, polygonal/ovoid shaped cell and nucleus

45
Q

mesenchymal cells characteristics on the slide

A

individually or loose clusters, indistinct cytoplasmic borders (IMP), often poor exfoliation, often fusiform cells, oval elongated nucleus,

46
Q

mesenchyla cells trick

A

fibrosis or fibroplasia if in low numbers –> don’t over interpret!

47
Q

criteria of malignancy?

A

pleomorphism (anisocytosis, anisokaryosis), macrocytosis, macrokaryosis/ increased nuclear size, nucleolar size and shape/ multinucleation (2 or more nuclei, off numbers of nuclei), abnormal mitotic figures (quite rare to see)

48
Q

check macrocytosis/macrokaryosis trick

A

compare with neutrophils

49
Q

interpreting criteria of malignancy

A

need to see consistently 3 criteria of malignancy, but if fewer than 3 –> benign lesion or aspiration of normal tissue

50
Q

caution with interpretation inflammation

A

inflammation –> can cause atypical cellular morphology

51
Q

caution with interpretation damaged cells

A

shouldn’t interpret

52
Q

exceptions to the rules in lymph nodes

A

monomorphic is abnormal, polymorphic is normal

clinical pathology (3 decks)

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