INTRODUCTION TO PATHOLOGY
SUNILKUMAR.P
Haematology & Transfusion Medicine
St.John’s Medical College Hospital Bangalore

• Overview of pathology..
• What is pathology (Definition)..
• Branches of pathology..
• Evolution of pathology…
• Histopathology..?
• Clinical Pathology…?
• Haematology….?

“Pathos” = suffering or disease
“logos” = study
Study of diseases
Study of the structural and
functional disease.

Definition
• The word “ Pathology” is derived from two
Greek words – Pathos means “Suffering” and
logos meaning “ study”.
• Pathology is thus , scientific study of structure
and function of the body in disease

SUBDIVISIONS OF PATHOLOGY
• Human pathology is the largest branch of
pathology.
• It is conventionally divided in to
• A. General pathology = dealing with general
principles of disease
• B. systemic pathology= deals with study of
diseases pertaining to specific organs and
body systems.
.

Subspecialties in Pathology
• 1.Histopathology-
• a. Surgical pathology
• B. Forensic pathology & autopsy work
• C. Cytopathology
• 2. Haematology
• 3.Chemical pathology
• 4. Immunology
• 5.Experimental pathology
• 6.Geographic pathology
• 7.Medical Genetics
• 8.Molecular Pathology.

HISTOPATHOLOGY
HAEMATOLOGY
CLINICAL PATHOLOGY

Histopathology
Definition it is a branch of pathology
which deals with the study of disease in
a tissue section.

The tissue undergoes a series of steps before it reaches the
examiners desk to be thoroughly examined microscopically to
arrive at a particular diagnosis.
To achieve this it is important that the tissue must be prepared
in such a manner that it is sufficiently thick or thin to be
examined microscopically and all the structures in a tissue may
be differentiated.

What is Clinical pathology…?
• The branch of pathology dealing with the
study of disease and disease processes by
means of chemical, microscopic, and serologic
examinations.

Haematology…??
• the branch of medicine involving study and
treatment of the blood.

INTRODUCTION TO DEPARTMENT OF
HISTOPATHOLOGY
Histopathology is the department of clinical lab which deals
with the study of diff types of tissues
The department is based on following benches:
• Processing
• Gross
• Tissue processing
• Embedding,cutting,H&E
• Immunohistochemistry
• Special stains
• Cytology
• Cytogenetics

WHAT IS HISTOPATHOLOGY?
Greek word
Histo- tissue
Pathos- disease suffering
• refers to the microscopic examination of tissue in order to
study the manifestations of disease.
• histopathology refers to the examination of a biopsy or
surgical specimen by a pathologist,
• after the specimen has been processed and histological
sections have been placed onto glass slides

BENCHES IN HISTOPATHOLOGY
1.PROCESSING
Specimen categories
• Tissues (with history)
• Bone (with x- ray)
• Autopsy (consent form)
• Body fluids
• CSF

BENCHES IN HISTOPATHOLOGY contd..

BENCHES IN HISTOPATHOLOGY contd..
2.GROSS SECTION (grossing)
• specimens are inspected with the bare eye
• diagnostic information
• further microscopic examination.
Tissues are saved in different cassettes having different color
• Yellow (liver, renal)
• Green (routine)
• White(bones)
• Grey(skin)
• Pink(lymph nodes)

BENCHES IN HISTOPATHOLOGY contd..

BENCHES IN HISTOPATHOLOGY contd..
3.TISSUE PROCESSING
• fixing tissue into paraffin
• dehydration and clearing
• tissue is infiltrated with the embedding agent, (paraffin)
• Tissue processing is always automated for the large volumes of
tissues.
• Automation consists of an instrument that moves the tissues
around through the various agents on a preset time scale.

BENCHES IN HISTOPATHOLOGY contd..

BENCHES IN HISTOPATHOLOGY contd..
4.EMBEDDING
• Orientation of tissue in melted parafin which provide a firm
medium for keeping all parts of tissue intact
• Temp of parafin (58-60 C)
• Instrument used (embedding station)
CUTTING
Microtome used for cutting about 3-5 micron
H&E
Hematoxlyin (water based dye)
Eosin(counter stain)
They stains nucleus & cytoplasm

BENCHES IN HISTOPATHOLOGY contd..

BENCHES IN HISTOPATHOLOGY contd..

BENCHES IN HISTOPATHOLOGY contd..
5.IMMUNOHISTOCHEMISTRY
• Ag-Ab specific reaction
• Clinical diagnosis and distinguishing diagnosis of tumor
histogenesis
• Can be used to locate particular cells and proteins
• Can be used to identify cellular events – e.g.apoptosis

BENCHES IN HISTOPATHOLOGY contd..

BENCHES IN HISTOPATHOLOGY contd..
6.SPECIAL STAINS
• Required when diagnosis is not identified with H&E staining
Some of the stains used are
• Connective tissue ( rapid trichome)
• Nucleic acid (methylene green pyronin)
• Carbohydrates(PAS & PASD)

BENCHES IN HISTOPATHOLOGY contd..

BENCHES IN HISTOPATHOLOGY contd..
7.CYTOGENETICS
Study of chromosomes and its abnormalities
• chromosome number
• structure
• function
• behavior in relation to gene inheritance,
• organization and expression
Types of disorders:
• Deletions
• Inversions
• Translocation
• Addition(insertion)

BENCHES IN HISTOPATHOLOGY contd..
Types of specimen
• Blood
• Bone marrow
• Amniotic fluid
Procedures done
• Karyo typing
• G-banding
• FISH

BENCHES IN HISTOPATHOLOGY contd..

BENCHES IN HISTOPATHOLOGY contd..
8.CYTOLOGY
Study of cells to know the infection,pre malignant and
malignanent changes
2 types of samples
• Gyane
(pap smears)
• Non Gyane
(bodyfluids,CSF,urine,pericardial,pleural.asitic.synovial)

BENCHES IN HISTOPATHOLOGY contd..
Procedures done in cytology
• FNAC
• FNAB
Staining in cytology
• H&E
• Pap
• Dry (rapi)
• Gimesa

BENCHES IN HISTOPATHOLOGY contd..

BENCHES IN HISTOPATHOLOGY contd..
9.SEMEN DR
Fresh sample of seminal fluid is examined for :
• Liquefaction
• Motility
• Number
• Morphology
Elements of analysis
• Quantity
• Color
• Liquefaction
• pH

BENCHES IN HISTOPATHOLOGY contd..
Tests done are
• Detailed report
• IUI (intra uterine insemination)
• Anti sperm antibody

BENCHES IN HISTOPATHOLOGY contd..

THANKS