Histopathologic Techniques (M) Flashcards
The histopathology section is concerned w/ what?
It is concerned w/ the dx of abnormalities within tissues and cells by microscopic examination
What are the meanings of the ff Greek words w/c are the origin of the term “histopathology”:
1) “HISTOS”
2) “PATHOS”
3) “LOGOS”
1) Tissues
2) Suffering / diseases
3) Study of
What is histology?
It is the microscopic study of normal tissues of the body
What is histopathology?
It is the microscopic study of tissues affected by disease
What are histologic or histopathologic techniques?
These are the procedures adopted for the preparation of material for such studies
What are the usual procedures on obtaining tissues for examination?
1) Surgery
2) Biopsy
3) Autopsy
The tissues obtained for examination range in what (in terms of size)?
From very large sxs or whole organs to tiny fragments of tissue
What are the surgical procedures that are usually performed to obtain sp type of tissue that are submitted to a histology lab for processing (/ what are the procedures for examining fresh tissue)?
1) Fine needle aspiration (FNAB)
2) Core needle biopsy
3) Incisional biopsy
4) Excisional biopsy
5) Punch biopsy
6) Shave biopsy
What are the characteristics of FNAB?
1) It is the simplest procedure
2) It is the least invasive test
What / how is FNAB done (explain its principle) and what is the cons of this procedure?
The smallest needle is used to simply remove cells from the area of abnormality
However, this is not always adequate to obtain a dx, depending on the area to be biopsied
How is core needle biopsy done (explain its principle)?
It removes not only cells, but also a small amt of the surrounding tissue
What is the pros of core needle biopsy?
It provides additional info to assist in examination of the lesion
How is incisional biopsy done (explain its principle)?
This procedure takes out even more surrounding tissue. It takes out some of the abnormality, but not all. The doctor will slice into the lesion and remove only a portion of it
If after the conduction of incisional biopsy, the lesion obtained is found to be cancerous, what should / may be done?
Further surgery may be needed to remove or excise the entire lesion
How is excisional biopsy done (explain its principle)?
In this procedure, the entire area in question is generally removed
What are the characteristics of punch biopsy?
1) It is considered as the primary technique for obtaining full diagnostic full-thickness sxs
2) It is easy to learn
What are the requirements for the lab professional that will do punch biopsy?
The procedure requires basic general surgical and suture-tying skills
How is punch biopsy done (explain its principle)?
It involves the use of a circular blade that is rotated down through the epidermis and dermis, and into the subcutaneous fat, yielding a 3 - 4 mm cylindrical core of tissue sx
How is shave biopsy done (explain its principle)?
It is the procedure where small fragments of tissue are “shaved” from a surface
At what surface (/ part of the body) is shave biopsy usually done?
Skin
Sxs are usually received in the presence of what?
Fixative (/ preservative)
Can sxs sometimes arrive fresh in the histopath lab?
Yes
What should be done to fresh sxs once they arrived (/ received) in the lab?
These must be immediately fixed
What should be present along w/ the tissue sxs received in the surgical pathology lab?
These should have a request form
What should be listed in the request form (w/c should come along the tissue sxs)?
1) Pt info
2) Clinical history
3) Description of the site of origin
What should be done to sxs that will serve as their label?
The sxs are accessioned by giving them a number that will identify each sx for each pt
What is impt to be done to minimize the risk of mislabeling?
It is impt that sxs are properly identified
Methods of tissue examination may vary accdg to what?
Structural and chemical components of the cells to be studied
Methods of tissue examination depends on what?
Nature and amt of tissue to be evaluated
Fresh tissues are usually examined in what circumstance?
When there is a need for evaluation
What is the better and more effective means of studying tissues (whether normal or abnormal)?
By examination of adequately preserved sections and smears that are stained to demonstrate sp structures
What should be done to glass slides for permanent keeping?
These should be mounted w/ coverslips for permanent keeping
True or False
Examination may be done on fresh or preserved tissues depending on necessity
True
What are the advantages of examining fresh tissues?
1) These tissues can be examined in the living state
2) Since these tissues can be examined in the living state, protoplasmic activities can be observed
What are the exs of protoplasmic activities w/c are done by fresh tissues?
1) Motion
2) Mitosis
3) Phagocytosis
What is the disadvantage of examining fresh tissues?
Since these tissues are examined in the fresh state w/c is not permanent, this is the reason / is liable to develop the changes that have usually been observed after death
What are the methods for fresh tissue examination?
1) Teasing or Dissociation
2) Squash Preparation (Crushing)
3) Smear Preparation
a. Streaking
b. Spreading
c. Pull-Apart
4) Touch Preparation (Impression Smear)
What is the process (/ steps) of teasing?
1) A selected tissue sx is immersed in isotonic solution (such as normal saline or Ringer’s solution) in a petri dish or watch glass
2) It is carefully dissected w/ a needle and separated by direct or zigzag spread using an applicator stick
3) Selected pieces of the tissue are transferred carefully to a microscope slide and mounted as a wet preparation underneath a cover glass
- > care being taken to avoid the formation of bubbles
4) It is either stained w/ a supravital dye or examined unstained by phase contrast or bright field microscopy
The preparations are not permanent
What is the advantage of the application of teasing as a method of fresh tissue examination?
The procedure has the advantage of permitting the cells to be examined in the living state
What is the result (/ benefit) of using phase contrast microscope in terms of the examination of fresh tissue?
The use of phase contrast microscope greatly increases the structural detail of the cells examined in the living state w/c allows movement and mitotic division to be observed
What stain can be used in teasing?
Methylene blue
What is the process (/ principle) of squash preparation?
Small pcs of tissue are placed in the microscopic slide and forcibly compressed w/ another slide or w/ a cover glass
If necessary, a supravital stain may be placed at the junction of the slide and the cover glass, and allow to be absorbed by the tissue through capillary action
What should be the size (in diameter; in mm) of the tissue that will be used in squash preparation?
Not 1 mm >
The method of preparing the smears differs depending on what?
Depending on the nature of the material to be examined
What is the general rule (/ procedure) for smear preparation?
Smears are made either by spreading the selected portion of the sx over the surface of the slide w/ a platinum loop
What is the alternative way of making / preparing smears?
An apposition smear can be made using a 2nd slide to obtain a relatively uniform distribution of secretion
What should be done when preparing smears?
Avoid making too thin / too thick smears
Why are too thin or too thick smears should be avoided?
Because they make the tissues less suitable for examination
True or False
Smears may be examined either as fresh preparations similar to that described for teased preparations, or by using a supravital staining technique
True
How can smears be made permanent?
Smear preparations can be made permanent by fixing them while still wet
What is the importance of staining smear preparations?
To demonstrate sp structures and inclusions
True or False
The cleared sx (in smear prep) should be mounted beneath a cover glass w/ the use of a suitable mounting medium
True
The procedure of smear preparation is useful for preparing smears of what?
Thick secretions such as:
1) Serous fluids
2) Concentrated sputum
3) Enzymatic lavage sxs from the GIT
4) Blood smears
The technique of smear preparation is especially useful in what?
Cytological examinations, particularly for cancer dx
What is the process of streaking (as a type of smear prep)?
With an applicator stick or a platinum loop, the material is rapidly and gently applied in a direct or zigzag line throughout the slide, attempting to obtain a relatively uniform distribution of secretion
What should be avoided when streaking?
The formation of too thin or too thick smears
Why should the formation of too thin / too thick smears be avoided (in streaking)?
Because they make tissues unsuitable for examination
How is spreading done?
A selected portion of the material is transferred to a clean slide and gently spread into a moderately thick film by teasing the mucous strands apart with an applicator stick
What is the comparison between the process of streaking and spreading?
The process of spreading is a little more tedious > streaking
What is the advantage brought by spreading?
It has the advantage of maintaining cellular interrelationships of the material to be examined
Spreading is especially recommended for smear preparations of what?
1) Fresh sputum
2) Bronchial aspirates
3) Thick mucoid secretions
How is pull-apart (w/c is a type of smear prep) done (explain its principle)?
1) This is done by placing a drop of secretion or sediment upon one slide and facing it to another clean slide
2) The material disperses evenly over the surface of the two slides
3) Slight movement of the two slides in opposite directions may be necessary to initiate the flow of
materials
4) The two slides are then pulled apart with a single uninterrupted motion, and the specimen is placed under the microscope for immediate examination, or applied with vital stains
What is the characteristic of touch preparation?
This is a special method of smear preparation
How is touch preparation done?
The surface of a freshly cut piece of tissue is brought into contact and pressed on to the surface of a clean glass slide, allowing the cells to be transferred directly to the slide for examination by Phase Contrast microscopy or staining for light microscopic study
What is the advantage brought by touch preparation?
The cells may be examined w/out destroying their intercellular relationship
In order to enable the patho to diagnose the presence / absence of disease, what is needed to be done by the histotechnologist?
The histotechnologist needs to produce a tissue section of good quality
Why should the histotechnologist need to produce a tissue section of good quality?
Because this allows for adequate interpretation of microscopic cellular changes
What are needed to be done to solid tissues?
These are needed to be fixed and processed
Why is it needed to fix and process solid tissues?
To preserve the structures of these tissues
After fixing and processing the solid tissues, what should be done?
These tissues should be impregnated w/ an appropriate hardening substance