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The wordThe word pathologypathology is derived from twois derived from two
Greek wordsGreek words-- pathospathosmeaning sufferingmeaning sufferingand and logoslogosmeaning study.meaning study.
Thus, pathology is the scientificstudy ofThus, pathology is the scientificstudy ofdiseasesi.e. it is the study of abnormaldiseasesi.e. it is the study of abnormal
form and function and the relationshipform and function and the relationship
between them.between them.
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11-- EtiologyEtiology (Itscause).(Itscause).
22-- PathogenesisPathogenesis ( Mechanism of( Mechanism ofdevelopment).development).
33-- Morphologic changesMorphologic changes (gross and(gross and
microscopic pictures).microscopic pictures).44-- Functional derangementFunctional derangement ((clinicalclinical
significance of the disease).significance of the disease).
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11-- NecropsyNecropsy( Autopsy).( Autopsy).
22--BiopsyBiopsy..
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The study of organs and tissues removedThe study of organs and tissues removed
from thefrom the dead bodydead body forverification of theforverification of the
clinical diagnosis and treatment of theclinical diagnosis and treatment of the
disease .disease . Includes: gross & microscopicIncludes: gross & microscopic
examination.examination.
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Pathological study ofsurgically removedPathological study ofsurgically removed
tissues or organstissues or organsduring lifeduring life for diagnosisfor diagnosis
& therapy.& therapy. Includes: gross & microscopicIncludes: gross & microscopic
examination.examination.
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Types of biopsiesTypes of biopsies
Tissue biopsy Cytology
11. Surgical biopsy:. Surgical biopsy:
a) Incisional biopsy.a) Incisional biopsy.b) Excisional biopsy.b) Excisional biopsy.
22. Tru cut (core) needle biopsy.. Tru cut (core) needle biopsy.
33. Endoscopic biopsy.. Endoscopic biopsy.
11. Exfoliative cytology.. Exfoliative cytology.
22. Fine needle aspiration. Fine needle aspiration
Cytology (FNA) .Cytology (FNA) .
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Incisional biopsy:Incisional biopsy: Part of the lesion isPart of the lesion isremoved.removed.
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Excisional biopsyExcisional biopsy
The entire organ is removed
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--A small cylinder of tissue is removed from aA small cylinder of tissue is removed from a
lump using alump using a cutting needlecutting needle ..
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Core needle biopsyCore needle biopsy
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This type of biopsy is performed using anThis type of biopsy is performed using an
endoscopeendoscope introduced through a naturalintroduced through a natural
body orifice (e.g. rectum) or a smallbody orifice (e.g. rectum) or a smallincision (e.g. arthroscopy).incision (e.g. arthroscopy).
A small forcepsisused to take a sampleA small forcepsisused to take a sample
from the lesion.from the lesion. Samples are small fragments.Samples are small fragments.
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Endoscopic biopsyEndoscopic biopsy
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Endoscopic biopsyEndoscopic biopsy
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It is the study ofindividual cells.It is the study ofindividual cells.
Cytology includes:Cytology includes:
11.Exfoliative cytology..Exfoliative cytology.
22.Fine needle aspiration cytology. (FNA)..Fine needle aspiration cytology. (FNA).
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Is the study ofcellsin smears preparedIs the study ofcellsin smears prepared
fromfrom exfoliated cellsexfoliated cells..
e.g: pleural effusione.g: pleural effusion urineurine smear fromsmear fromcervix .cervix .
Used as a screening test forcancerinUsed as a screening test forcancerinpatients who have no clinical evidence ofpatients who have no clinical evidence of
the disease.the disease.
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FNA isused for preoperative assessmentFNA isused for preoperative assessment
ofofpalpablepalpable lesions.lesions.
--Thisinvolves the aspiration ofcells or fluidsThisinvolves the aspiration ofcells or fluids
from masses that occurin palpable sitesfrom masses that occurin palpable sites
e.g.e.g. breast, thyroid & lymph nodesbreast, thyroid & lymph nodes..
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ThyroidThyroid
BreastBreast
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--The aspirated cells are smeared,stained &The aspirated cells are smeared,stained &examined.examined.
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--For diagnosis withinFor diagnosis within minutes while surgery isminutes while surgery is
taking placetaking place in suspected cases ofcancer.in suspected cases ofcancer.
--Uses:Uses:
11.Determine the nature of the lesion e.g..Determine the nature of the lesion e.g.breastbreast
lumplump..
22.Determine the adequacy ofsurgical margins.Determine the adequacy ofsurgical margins
e.g .e.g . malignant ulcermalignant ulcer..33.. In sentinel LNIn sentinel LN procedure, a LNcontainingprocedure, a LNcontaining
tumour tissue prompts further LN dissectiontumour tissue prompts further LN dissection
while a benign LN will avoid such a procedure.while a benign LN will avoid such a procedure.
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For frozen section technique, the tissue isFor frozen section technique, the tissue is
always transportedalways transported freshfresh (unfixed).(unfixed).
The tissue isThe tissue isfrozenfrozen and then sectioned.and then sectioned.
The sections are ready forThe sections are ready forstainingstaining..
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Adequate.Adequate.
Representative:Representative:
Piece of tissue submitted must be from thePiece of tissue submitted must be from thelesion & preferably include an adjoininglesion & preferably include an adjoining
area of healthy tissue.area of healthy tissue.
Labeled.Labeled.Combined with adequateCombined with adequate clinicalclinical
information.information.
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1. Fixation:1. Fixation:
10%10%formalinformalin (most commonly used).(most commonly used).
Other fixatives:Other fixatives:
-- 95% alcohol (in cytologicsmears)95% alcohol (in cytologicsmears)
-- Liquid Nitrogen (in frozen sections )Liquid Nitrogen (in frozen sections )
Uses:Uses:
1.Prevents autolysis.1.Prevents autolysis.
2.Hardens the tissues.2.Hardens the tissues.
3.Preserves the specimen.3.Preserves the specimen.
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22.Dehydration:.Dehydration:
-- By passing the tissue in ascending gradesBy passing the tissue in ascending grades
of alcoholof alcohol 7070%,%,9595% &% & 100100%.%.
33.Clearing :.Clearing :
-- by using certain reagents( e.g. Xylol).by using certain reagents( e.g. Xylol).
44..ImpregnationImpregnation in paraffin wax (soft paraffin):
--Done automatically by an electricDone automatically by an electricapparatus.apparatus.
55.Blocking out :.Blocking out : in hard paraffin wax.in hard paraffin wax.
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66.Sectioning :.Sectioning :
-- section cutting by microtome.section cutting by microtome.
77.Staining:.Staining:-- H & Estain OR Special stains.H & Estain OR Special stains.
88.Mounting:.Mounting:
--Covering the stained section by aCovering the stained section by acolourless medium that preserves thecolourless medium that preserves thesection.section.
--The commonest mounting medium isThe commonest mounting medium is
canada balsam.canada balsam.
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Tissue that has been cut andTissue that has been cut and
placed in cassettesplaced in cassettes
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Tissue embedded in paraffinTissue embedded in paraffin
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Cutting sections with theCutting sections with the
microtomemicrotome
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Formation of slidesFormation of slides
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Fat stained black by osmic acidFat stained black by osmic acid
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IronIron
overloadoverload
in thein the
spleenspleen
Iron stained blue by prussian blue
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Glycogen stained red by PASGlycogen stained red by PAS
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Mucin stained redMucin stained red
by mucicarmineby mucicarmine
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11.The following substances can.The following substances can
be used as fixatives except:be used as fixatives except:
a)Formalin.a)Formalin.
b)A
lcohol.b)A
lcohol.c)Saline.c)Saline.
d)Liquid nitrogen.d)Liquid nitrogen.
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22.Which of the following can be.Which of the following can be
used as a clearing agent ?used as a clearing agent ?
a)Xylol.a)Xylol.
b)formalin.b)formalin.
c)water.c)water.
d)Alcohol.d)Alcohol.
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33.Specimens sent for frozen.Specimens sent for frozen
section are preserved in:section are preserved in:
a)Formalin.a)Formalin.
b)Saline .b)Saline .
c)Alcohol.c)Alcohol.
d)None of the above.d)None of the above.
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A
A4848--yearyear--old male comes to the physician becauseold male comes to the physician becauseof an odd discoloration of his skin.of an odd discoloration of his skin.
A full work up for this abnormal skin pigmentationA full work up for this abnormal skin pigmentation
shows diabetes mellitus & increased levels of serumshows diabetes mellitus & increased levels of serum
ferritin & transferrin saturation. A liver biopsy wasferritin & transferrin saturation. A liver biopsy was
done . In addition to H&E ,done . In addition to H&E ,which of the following iswhich of the following isthe most appropriate stain to use for this specimen?the most appropriate stain to use for this specimen?
a)Congo red.a)Congo red.
b)Periodic acidb)Periodic acid-- Schiff.Schiff.
c)Prussian blue.c)Prussian blue.
d)Mucicarmine.d)Mucicarmine.
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