Fresh Frozen Section (F) Flashcards
Fresh frozen section is also known before as what?
Intraoperative consultation
What is fresh frozen section (what is its principle)?
It is one of the special processing techniques w/c involves rapidly preserving tissue blocks by freezing to produce instant cessation of cellular activity thereby preventing chemical alteration of tissue constituents and displacement of cellular tissue components
What are the 2 well-known procedures that are used back then (aside from using cryostat for fresh frozen section as of today)?
1) Freeze-drying
2) Freeze substitution
What is the principle of freeze-drying?
It entails rapid freezing (/ quenching) and removing of H2O (/ desiccation) by a physical process from the frozen tissue block w/out using chemical fixative
What is the time duration of the process of quenching step?
2 - 3 secs
What is used in quenching step?
Isopentate / propane-isopentane mixture
What is the characteristic of isopentate/propane-isopentane mixture used in quenching step?
It is chilled to -160 to -180 DC w/ liquid N
What is used for / in desiccation?
High vacuum drying app (maintained at -30 to -40 DC)
What is the time duration where complete desiccation occur?
Within 24 - 48 hrs
What are the characteristics of freeze substitution?
1) It is basically similar to freeze-drying (but it does not use the vacuum drying app)
2) It is more economic > freeze-drying
Since vacuum drying app is not used in freeze substitution, what is the process done?
It fixes the tissue via the use of chemicals
What are the chemicals that can be used for fixing the tissue (via freeze substitution)?
1) Rossman’s fluid
2) Osmium tetroxide (in 1% acetone; for 1 - 6 days at -60 to -70 DC)
What is the composition of Rossman’s fluid?
80 mL saturated picric acid (in 95% alcohol) + 185 mL formaldehyde
What is done after fixing the tissue (in freeze substitution)?
Dehydration (via the use of absolute alcohol [at room temp] / in acetone [at -70 DC])
As of today, what is the machine used for fresh frozen section?
Cryostat
What are the legitimate purposes of frozen section (FS)?
1) To establish the presence and nature of a lesion
2) To determine the adequacy of surgical margins
3) To establish whether the tissue that is obtained contains diagnosable material or whether additional sampling is needed
What did Juan Rosai said (in relation to FS)?
“The real aim of the procedure is to influence the course of the operation”
What are the parts of cryostat?
1) Power
2) Light
3) Temp control
4) Chuck temp
5) Cutting action
6) Section
7) Downstroke speed
8) Upstroke speed
9) Chuck tightening lever
10) Blade
11) Blade adjusting lever
12) Mechanism lever
13) Roll bar
14) Collecting tray
15) Coarse control
16) Section thickness
17) Blade adjusting lock
18) Roll bar lever
19) Chuck
20) Blade guard
What are the materials needed for doing FS’?
1) Embedding medium (OCT)
2) Freezing agent
What should be done after obtaining the tissue (from the produced slide)?
Rapid fixation
What is used for rapid fixation?
95% ethanol
What will be the result if there is a delay in fixing the tissue (for FS’)?
There will be significant drying artifact
What should be done after fixing the slide?
Staining of the sections
What are the things that should be done after doing FS’?
1) Relaying the findings
2) Giving suggestions on how to proceed (done by / between pathos and clinicians)
3) Dx given verbally (/ discussed by the patho) should be transcribed verbatim (in an appropriate form)
Who is the professional that can do the transcribing of the verbal dx given by the patho?
Histotech
What should be done to the transcription done by the histotech?
A copy of it should be inserted into the chart
What are the true limitations of the procedure (for FS’)?
1) Time
2) Limited special stains and studies
3) Lack of consultation
4) Freezing artifacts
a. Ice crystals (in edematous stroma)
b. Compression artifacts
c. Nuclear ice crystals
d. Nuclear chromatin changes (in frozen control)
What are the avoidable limitations of the procedure (for FS’)?
1) Drying artifacts
2) Sampling error
3) Fat
4) Quality of section is inferior
5) Inconsistency of training and performance
6) Embedding
What is the statement that is related w/ FS’?
One must know what excellence looks like and sounds like in order to begin to approximate it. In all forms of art one can only achieve excellence if they are aware of all the ways to make mistakes and are aware when they are happening
