4. Histopathology and cytopathology lab Flashcards
what do histopathologists do?
make diagnoses and assess how far things have got (stages of cancer)
monitor disease and treatment
what do histopathologists specialise in?
interested in tissues: biopsies, resection specimen, frozen sections, post-mortems
what do cytopathologists specialise in?
interested in cells: smears, fine needle aspirates
what needs to be considered by histopathologists studying biopsies?
- if the biopsy obtained is normal
- whether people who are presenting with clinical symptoms have a normal biopsy
- if there is inflammation and why
- if there is malignancy
what needs to be considered by histopathologists studying resection specimens?
- how far the disease has spread
- if the disease has entered different parts of the body/lymph nodes
what needs to be considered by histopathologists studying frozen sections?
whether masses are benign or malignant (if there is malignancy the surgeons do a full resection to decide if there is something else going on)
what needs to be considered by histopathologists studying post-mortems?
whether a hospital or coroner’s post-mortem needs to be done
how are sections obtained?
- the specimen must be properly labelled
- all samples should be fixed in formalin (cross-links proteins and stops tissue decomposing)
- sample is embed in paraffin wax (allowing thin sections to be cut)
- section is stained and looked at under a microscope
what is done with the sections?
- the stain applied is haematoxylin and eosin
- if the patient is believed to have TB the stain given is Ziehl-Neelsen
- specific antigens can be identified using antibodies
- molecular tests can then be carried out
how long does a histopathology take to reach the clinician?
frozen sections: 30mins
biopsies: 2-3days
resection specimens: 5-7days
what does cytopathology involve?
fine needle aspiration
what is immunocytochemistry?
CD31 staining done to show the vascular tumour infiltrating collagen bundles
