Histopathology Flashcards
What is histopathology?
Deals with tissues, examining the architecture of the tissue; observations used in diagnosis, as well as towards informing the efficacy of a particular treatment
What are tissue samples?
Biopsies, resection specimens, frozen sections, and post-mortems
What are biopsies?
Concerns small sections of tissues removed from the patient; immersed in a formalin solution that preserves the tissues by cross-linking proteins.
What is formalin?
Preserves tissues by cross-linking proteins, samples are embedded in paraffin wax, enabling thin sections to be cut by a microtome.
Sample mounted on a microscope slide for preparation prior to analysis
What is the main function of a biopsy?
As a diagnostic tool
Which chemical stains are used for cells in the biopsy section?
Haematoxylin and Eosin staining used to identify nuclei and cytoplasmic granules of leukocytes
Which type of stain will stain acid-fast bacteria red, aiding in diagnosis for TB infection?
Ziehl-Neelsen stain
What are resection specimens?
Sourced from tissue removed from surgical procedure, processed as for a biopsy
What are resections used for?
To identify the stage and progression of the disease (cancers, diagnostic too for further treatment)
Why are tissues donated to biobanks?
Used to inform genomic studies of the disease process
Which sample is taken during surgical procedures and examined by pathologists in real time?
Frozen sections
How are sections frozen?
By cryostat, cut then mounted on glass slide and stained for biopsies
Why are frozen sections used?
Rapid diagnosis, relayed back to the surgeon to inform the surgery. Establishes presence & quantity of cancerous tissue, as well as identifying other pathological processes
Fresh tissue sample w/o formalin
How long are frozen sections stored and used for?
30 minutes
What is the timescale for biopsies?
2-3 days