lecture 2 Flashcards
what is the only way to do a diagnosis?
look at the cells (cytology) or tissue (histology)
biopsy techniques
needle, skin punch, grab biopsy, incisional biopsy, excisional biopsy
why is necrosis not good for biopsies?
not diagnostic quality
where would ideally do a biopsy?
best chance to get diagnostic sample
considerations for biopsy
do not predispose to local spread, do not compromise subsequent therapy
excisional biopsy vs incisional biopsy
excisional biopsy= whole lesion taken out / incisional biopsy= bit taken out
cytology def
ways of collecting cells, can give information about the cell population in that lesion (monomorphic/polymorphic…) can direct towards diagnosis
cytology techniques
impression smears, fine needle aspiration, cytospins of body fluids/effusions
fine needle aspiration (FNA)
upfront technique in most situations, needle of 23 gage : locate lesion in one hand, stab it in different directions –> collect sample of whatever is in that region –> make smear by crossing one slide over the other –> cytology stain
advantages of cytology
quick & cheap, valuable info on type of cell type
disadvantage of cytology
cant’ grade tumour
grades in tumours
grade 1 is benign(ish), high /grdae 3 tumours= malignant, can only achieve that with cytology
when is cytology useful
enlarged lymph nodes, lesions in cell body BUT cautious –> can cause haemorrhage or tract them along internal tissue (eg bladder tumours are very sticky tumours)
limitations of cytology
soft tissue sarcomas, splenic lesions –> can get haemorrhagic lesions, not uncommon in labradors, german shepherds etc
splenic tumours and mammary tumours best outcome
take them out