BM422 - Block C (surgical histopathology)

clinical labs can receive small or large specimens: what specimens are considered small/large?

small = core biopsies

>>> associated with diagnosis

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large = resections

>>> associated with a therapeutic removal of the tissue + staging

what is the basic histopathological preparation process? (regardless of size)

fixing (formalin)

>>>

embed in cassette (paraffin)

>>>

cut/section

>>>

stain and coverslip

>>>

assess

how does the histopathological preparation process differ for small and large specimens?

fixing:

>>> small (or some resections) can be immersed in formalin

>>> other resections require inflation and insertion of formalin (e.g., lung)

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embedding:

>>> small can be placed as one unit in a cassette

>>> large requires dissection and block selection for placement in cassette (want to include margin of resection, multiple tumour areas, uninvolved tissue, and lymph)

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cutting:

>>> small require levelling (since the entirety of the specimen is within one block - standard is 3 levels)

>>> large require just one cut (since already multiple blocks)

what analysis can be carried out on a sectioned tissue?

H+E staining for basic assessment

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special staining (for specific cell structure visualisation (e.g., mucicarmine for mucin))

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IHC (Ab-targeting of cellular structures/proteins)

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molecular biology (e.g., PCR)

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cytogenetics (e.g., FISH)

what is digital histopathology?

the use of computer algorithms to assess histopathological specimens is a more robust manner

in general, what quality assurance is involved with surgical histopathology?

IQA and EQA

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CPA(UK) + UKAS (=accrediting bodies)