Introduction to
pathology
Dr. Amitabha Basu MD
What is Pathology ?
It is the study (logos) of the
sufferings (pathos).
It’s a laboratory
Basic Sciences
P
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Clinical Medicine
Various Divisions of pathology
1. Clinical Pathology
2. Molecular Pathology
3. Hematopathology
4. Histopathology
5. Cytopathology
6. Blood banking
Clinical Pathology
Automatic
Analyzer
Clinical pathology
►A
branch of pathology concerned with
patient care.
Molecular Pathology
Molecular Pathology
►A
branch of pathology concerned with
the study of the diseases and mechanisms of
disease on a molecular or chemical level.
Human immunodeficiency virus, viral particles at medium
magnification adjacent to cell surface, electron micrograph.
Hematopathology
Hematopathology
► This
branch deal with the Disease of
the Blood.
This peripheral blood smear is stained with the
Wright's stain. (Leishman stain)
Here is a laboratory instrument
called a Coulter Counter
CBC (complete blood count) :
from Coulter blood cell counter
Cytopathology: Study of cellular
change in the diseased tissue.
Cytopathology
Study of cell
Tissue composed of many cell
of similar function
Two methods to obtain the cells
1. Exfoliative cytology ( collect and
examine the cell that falls –off from the
tissue)
2. FNAC (Fine needle Aspiration Cytology):
cell obtained with a fine needle.
What is that mean ?
► Exfoliated
cells (
eg from Cervix)
for quick
diagnosis of
malignancy
► Stain Uses:
► Papanicolaou
Stain
Pap Smear
If there is malignancy- it will look like
this
Cervical Cytology
► It
helps in early diagnosis of cancer of
Uterine Cervix.
So, you can
prevent a
cancer like
this!!
FNAC [ fine needle aspiration
cytology ]
Cells obtained from an abnormal mass
in the body : EG Breast lump
Pathologist performing an FNAC from
thyroid and breast
Aspirated Thyroid cells shows features of
malignancy : Aspirated cells stained with
Giemsa Stain
It is quick.
Less expensive
No hospital stay
required
Histopathology
Study of tissue
Tissue composed of many cell
of similar function
Histopathology- a technique to identify a
disease by looking at the tissue!
House of final diagnosis.
► Tissue
is collected and fixed with formalinovernight- it takes time!.
► It is then embedded in paraffin and cut with
microtome- 3 micron thick.
► This thin tissue is then stained with Hematoxiline
& eosin( H&E) stain.
► Following that it is mounted with DPX and cover
slip.
Normal Squamous cell and Histopathology of
Squamous cell carcinoma.
Definition of histopathology:
Pathological Study of the minute structure,
composition, and function of diseased tissues.
Histopathology
An important procedure to rule out or
confirm malignancy.
Stain Used : Hematoxylin and Eosin Stain
[H&E]
Biopsy
► The
removal and examination of a sample
of tissue from a living body for diagnostic
purposes
Biopsy sample then sent to the
Histopathology laboratory
Tissue were kept in the Formalin for
Fixation and to avoid autolysis
Frozen section
► Paraffin
► If
section takes time---
you need a quick section…..we harden
the tissue by freezing it…frozen section.
Frozen Sections
►It
is necessary to get a rapid
diagnosis of a pathologic process.
► The
piece's are snap frozen in a cold liquid
or cold environment (-20 to -70
Celsius).
► Freezing makes the tissue solid enough to
section with a microtome.
Cutting a frozen section. Cryostat.
Use of frozen section technique.
1. To check to presence of tumor in surgical
resected ends, while removing a tumor
from the body.
2. To check for the presence of metastasis
tumor in lymph node.
3. To identify fat.
This is not enough!
So we need special stains!
Special steins and common Use
Periodic acid
Stain
Stain Glycogen Storage disease,
Ewing's sarcoma,
Candida.
Mucicarmine
Stain
Stain Mucin
Identify
adenocarcinoma
Prussian blue
reaction &
Perl's iron stain
Oil-O-Red stain
Stain
Iron
Hemochromatosis
Trichrome stain
Stain collagen
Stain Fat( in
Fatty Liver
frozen section)
Scar.
Special steins and common Use
leukocyte
alkaline
phosphatase
(LAP)
The
myeloperoxida
se (MPO) stain
Stain
Neutrophils(
normally
present)
Identify
myeloid cells
Low in Chronic
Myeloid
Leukemia
Acute
Myeloblastic
Leukemia.
Blood Bank
Blood Bank
► Optimal
Blood Testing, Preservation
and Utilization of Blood and blood
products.
Donate Blood to save a life
Welcome once again to the world of
Pathology
Why ? How ? Where ? = Answer this and you will
get your diagnosis
How to study pathology ? Easy
► Learn
► Why
is the disease = Etiology
► What are the types = Classification
► How the disease occur = Pathogenesis
► Where = Morphological Change of the organ
effected
► What happens then = Clinical significance.
Follow this pattern and you will never
forget pathology
Understanding of a few terms: and also study
pathology in this sequence.
1. Etiology
2. Pathogenesis
3. Morphology
1. Gross change of a diseased organ/tissue
2. Microscopical change of the tissue and
cells.
4. Functional Derangement and Clinical
Significance
Etiology
► Cause
of the disease.
► Example : Chronic Alcoholism is the
etiology of fatty liver.
Pathogenesis
Definition : Mechanism of disease
formation
► Alcohol
produce injury to the liver cells ,
following that Liver cells (Hepatocytes)
become unable to metabolize Fatty acid.
► And it accumulate in the liver cells to
produce fatty liver.
Pathogenesis : narrowing of the
coronary artery : Myocardial
Infarction.
Morphology : 2 parts
1. Gross visible change of a
diseased organ/tissue.
2. Microscopical change of the
tissue and cells.
Morphology: Gross change in the
diseased organ.
Morphology: Microscopical change
in the tissue / cells
Functional Derangement and Clinical
Significance
Signs and
Symptoms
Evaluation of
the
Disease
Prognosis
Cell and Pathology
► Structural
and Functional Change in the cell
is the basis of all forms of organ Injury.
Father of
Modern
Pathology
Rudolf Virchow
Learning
NICE TO
KNOW
AREA
MUST KNOW
AREA
GOOD TO
KNOW
AREA
Thank you.
Enjoy the subject and learn it.