His to Tech Frozen

8/9/2019 His to Tech Frozen

1/13

Frozen

Section

Biopsy

Ma. Minda Luz Meneses-Manuguid, M.D.


2/13

Frozen section biopsy

Biopsies are small samples of tissue taken from amass or tumor that are examined under amicroscope to make a diagnosis.

Biopsies are used most often to determine whether

cancer cells are present, although certain infectionsand other diseases can be diagnosed as well. A specific type of biopsy procedure called the

frozen section was developed in order to make arapid diagnosis of a mass during surgery.

The frozen section is a laboratory procedure toperform rapid microscopic analysis of a specimen. Itis used most often in oncological surgery. Thetechnical name for this procedure is cryosection.


3/13

Frozen Section Procedure

The surgeon removes a portion of the tissue mass. Thisbiopsy is then given to a pathologist.

The pathologist freezes the tissue in a cryostat machine, cuts

it with a microtome, and then stains it with various dyes sothat it can be examined under the microscope. Theprocedure usually takes only minutes.

The quality of the slides produced by frozen section is of

lower quality than formalin-fixed, wax-embedded tissueprocessing. While diagnosis can be rendered in many cases,fixed tissue processing is preferred in many conditions formore accurate diagnosis.


4/13

Technical aspects

The key instrument for cryosection is the cryostat, which isessentially a microtome inside a freezer.

The microtome is a very accurate "deli" slicer, capable ofslicing sections as thin as 1 micrometer. The usual histologyslide is cut at 5 to 10 micrometers.

The surgical specimen is placed on a metal hold and frozenrapidly to about 20 to -30 C. At this temperature, mosttissues become rock-hard. Usually, colder temperature isrequired for fat or lipid-rich tissue, and cooler temperaturefor skin. Each tissue has a preferred temperature forprocessing.

The specimen is embedded in a gel-like media known asOptimum Cutting Temperature (OCT) compound.


5/13

Technical aspects

tissue must be sufficiently cold & hard to preventcompression & displacement of cell & tissuestructures as the knife passes through. (if not cold

enough, tissue melts & becomes adherent to theknife; if too cold, tissue becomes brittle, itsresistance to cutting is increased, & it fragmentsupon cutting)

the knife must also be chilled & maintained at lowtemp.The cutting blade must be sharp and set at thecorrect angle.


6/13

Cutting temperatures

Recommended Temperatures for Cutting Unfixed FrozenTissues

Tissue Type Working TemperatureBrain -12 C

Liver, Lymph node -14 C

Kidney, Spleen -16 C

Muscle, Thyroid -20 C

Skin, Breast -25 C

Breast with Fat, Adipose tissue -30 C or below

Fixed Tissue -12 C to -17 C


7/13

Technical aspects

Subsequently the frozen tissue is cut with themicrotome portion of the cryostat, thesection is picked up on a glass slide andstained (usually with H & E)

The preparation of the sample is much morerapid than with traditional histology

technique (around 10 minutes vs 16 hours)

.However, the technical quality of thesections is much lower.


8/13

The intraoperative consultation is the name given

to the whole intervention by the pathologist:frozen section, gross evaluation, examinationof cytology preparations taken on the specimen(e.g. touch imprints), and aliquoting of the

specimen for special studies (e.g. molecularpathology techniques, flow cytometry). The report given by the pathologist is usually

limited to a "benign" or "malignant" diagnosis, and

communicated to the surgeonASAP

. The principal use of the frozen section procedure isthe examination of tissue while surgery is takingplace.


9/13

Indications for Frozen Section biopsy

Mohs surgery - a simple method for 100% margin-control of a surgical specimen. a sample of the suspected metastasis is sent for

cryosection. This will help the surgeon decidewhether there is any point in continuing theoperation. Usually, aggressive surgery is performedonly if there is a chance to cure the patient. If thetumor has metastasized, surgery is usually notcurative, and the surgeon will choose a more

conservative surgery, or no resection at all. Evaluation if surgical margin is free of tumor, anintraoperative consultation is requested to assessthe need to make a further resection for clearmargins.


10/13

Indications

In a sentinel node procedure: a sentinel nodecontaining tumor cells prompts a further lymphnode dissection, while a benign node will avoidsuch a procedure.

If surgery is explorative, rapid examination of alesion might help identify the possible cause of apatient's symptoms.

It is important to note, however, that thepathologist is very limited by the poor technical

quality of the frozen sections.A

final diagnosis israrely offered intraoperatively. Rarely, cryosections are used to detect the presence

of substances lost in the traditional histologytechnique, for example lipids. They can also be used

to detect some antigens masked by formalin.


11/13

Advantages of Frozen section biopsy If more tissue is needed to make an accurate diagnosis, thesurgeon is able to obtain an additional sample, avoiding a

second operation. If the tissue is determined to be cancerous and is amenable

to surgery, the mass can be removed at that time.

If the tissue is determined to be benign (not cancerous),then the mass may not always need to be removed and thesurgery can end.

The frozen section biopsy can help ensure that the massbeing removed is the intended tissue for removal.

It can help ensure that the entire mass and its surroundingborders are removed. It allows for the collection of proper tissue samples for

further scientific research. The surgeon and pathologist are able to collaborate to

care for the patient.


12/13

Frozen section biopsy

Sometimes pathologists are not able to determine thediagnosis based on the frozen section and insteadmust rely on the permanent section.

Although this takes longer than a frozen section(usually 1 day), the permanent section leads tobetter-quality microscope slides.

All biopsies are limited by the sample taken. Cancer

or other diseases may be so small that they are notpresent in the tissue sample but may still be presentelsewhere. Multiple biopsies may be needed tomake a diagnosis


13/13

Documents

His to Tech Frozen