Histopathology Flashcards
What does a histopathologist do?
Deals with tissues, examines the sections, and notes the architecture of the tissue and identify what it tells us about a particular condition
What does a cytopathologist do?
Deals with cells, takes them from the patient and prepares them for examination and then delivers their expert diagnosis on the cell sample.
What are the four tissue samples a histopathologist will work with?
- Biopsies
- Resection specimens
- Frozen Sections
- Post-Mortems
What are real-time examinations used for?
for surgical processes
What are biopsies?
Small sections of tissues removed from a patient
What solution are biopsy tissues placed in for preservation?
Formalin
How are biopsy samples preserved?
The formalin they are preserved in cross links the proteins and fixes the tissue
What are biopsy tissues embedded in to allow very thin sections to be cut?
Paraffin wax (2-3 micrometers thick)
What cuts the biopsy tissue into very small sections?
Microtome
What stain is used to identify the nuclei and cytoplasmic granules of leukocytes within tissues?
Haemotoxylin and Eosin (H&E)
What is used to stain acid fast bacteria?
Ziehl-Neelsen stain
What stain is used to aid the diagnosis of tuberculosis infection?
Ziehl-Neelsen
How long does the results of a biopsy take to reach the clinician?
2-3 Days
How long does it take for the results of a frozen section to reach the clinician?
30 Minutes
How long does it take for results of a resection specimen to reach the clinician?
5-7 days
What are resection specimens?
specimens are taken from tissue that has been removed as part of a surgical procedure and can be processed as for a biopsy.
What are resection specimens primarily used to do?
Look at the stage of disease
Why may tissue samples from resection specimens be donated to biobanks?
They may be used to inform genomic studies of the disease process
What is a frozen section?
A sample taken during a surgical procedure and examined by pathologists in real time
What is used to freeze the tissue?
Cryostat (a machine)
What happens to the frozen tissue from the frozen section?
it is frozen, cut, mounted on slides and stained as for biopsies
What are the requirements for tissue samples to be frozen?
Fresh and free of preservatives like formalin
What is a fine needle aspirate?
When a fine needle is inserted into a lesion and used to aspirate the cells out the lesion for anaylsis
Why is fine needle aspiration useful?
The needle can easily penetrate relatively inaccessible tissues without the need for surgery
e.g., thyroid nodule
What is the downside of fine needle aspiration?
the cytopathologist is only looking at cells and is unable to comment upon the likely architecture of the tissue.
Give an example of when both histopathology and cytopathology are used?
In the diagnosis of reactive lymphadenopathy
fine needle aspirate of enlarged lymph nodes and skin biopsy