Cytology in practice Flashcards
advantages of cytology
quick, easy cheap
non-invasive
can be good diagnositic tool
limitations of cytology
relies on sample quality
exp of examiner
histopath
more expensive
slower - 48h
tumour grading
immunhistochemistry more avaiable
what/where to sample - aspiration or imprints
superficial masses
lymph node
organs, deep masses
what/where to sample - fluid
body cavities
joints
resp tract
cerebrospinal fluid
fine needle biopsy
solid + fluid filled masses visual/ultrasound guidance similar to FNA but no -ve pressure insert into mass several times - more representative necrotic centre - sample wall + centre
fine needle aspiration (FNA)
only if needle biopsy unrewarding
needle in centre of mass, apply -ve pressure
repeat 2-3x for representative sample
release plunger before removing needle
touch impression (imprints)
good for excised tissue/superficial lesions
made before excised tissue in put in 10% buffered formalin + submitted for histopathology
imprints
use fresh cut surface of tissue
blot till dry
imprint directly onto slide
4-5 imprints per slide
collection of fluid
clot prevention - EDTA
bacteriology - sterile pot
slide prep - fresh
inflammation vs neoplasia
sample mostly infl cells (WBC) or tissue cells (neoplastic)
if both, exp needed - one could be primary cause and the other secondary
septic inflammation
bacteria/organisms
degenerate neutrophils
bacteria intracellular within neutrophils to be significant
if extracellular - contaminants
non-septic inflammation
no bacteria/organisms
neutrophils non-degeneratie
no identifiable bacteria
degenerative change in neutrophils
nuclear change
nucleus swells, loses lobulation + paler
secondary to release of bacterial toxins
incr numbers of macrophages - causes
granulomatous infl - mycobacterium sp
if neutrophils also - pyogranulomatous infl - fungal
either can be seen with foreign bodies
round cells
round/oval cell round nuclei well defined borders good cell yield advantage over histopathology
round cell tumours
lymphoma plasmacytoma histiocytoma hast cell tumour transmissable venereal tumour (TVT) (melanoma)
epithelial cells
in sheets/rafts/cluster cell-to-cell junctions nuclei round + in centre abudant cytoplasm good cell yield sebaceous, mammary, liver
mesenchymal cells
individual or clumps spindle - fusiform - stellate indistinct cell border long nucleus matrix production
cellular criteria of malignancy
anisocytosis - variation in cell size
macrocytosis - large cells
cell crowding
nuclear criteria of malignancy
anisokaryosis - varying nuclear size multinucleation - off numbers of nuclei macrokaryosis - giant nuclei high incr + abnormal mitotic figures nuclear-cytoplasmic ratio coarse chromatin nuclear moulding - deformation of nuclei by other nuclei
mesenchymal tumour - what to beware of
granulation tissue has malignant features
well differentiated sarcoma can look benign
take biopsy
mammary tumours
need to biopsy to differentiate between abscess, MCT or lipoma
malignant tumours with uniform cells
thyroid carcinoma
not seeing bacteria doesnt rule out ___
sepsis
