Histology(MTSTS1)

1. HISTOPATHOLOGY

2. Histopathology
Refers to the microscopic examination of tissue in order
to study the manifestations of disease. Specifically, in
clinical medicine, 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.
In contrast, cytopathology examines free
cells or tissue fragments.

3. Collection of tissues (Histopathological
examination of tissues starts with:
surgery, biopsy, or autopsy.)
NOTE:
The tissue is removed from the body, and then placed in
a fixative which stabilizes the tissues to prevent decay. The most
common fixative is formalin (10% formaldehyde in water).
The tissue is then prepared for viewing under
a microscope using either chemical fixation or frozen section

4. Biopsy
is a medical test commonly performed by a surgeon, interventional
radiologist, or an interventional cardiologist involving
sampling of cells or tissues for examination.
Biopsies are most commonly performed for insight into possible
cancerous and inflammatory conditions.

5. Conditions identified with biopsies
Cancer
Precancerous
conditions
Inflammatory
conditions

6. Cancer Pathologic examination of a biopsy can determine
whether a lesion is benign or malignant, and can
help differentiate between different types of cancer.
Precancerous
conditions
Easily detected and accessed
sites, any suspicious lesions
may be assessed. Originally, this
was skin or superficial masses.
X-ray, then later CT, MRI, and
ultrasound along with
endoscopy extended the range.
Inflammatory conditions
A biopsy of the temporal arteries is often performed for suspected
vasculitis. In inflammatory bowel disease (Crohn's disease and
ulcerative colitis), frequent biopsies are taken to assess the activity
of disease and to assess changes that precede malignancy.

7. Biopsied sites
Location Description
BONE MARROW
Since cells are formed in the bone marrow , a bone marrow
biopsy is employed in the diagnosis of abnormalities of
blood cells when the diagnosis cannot be made from the
peripheral blood alone. In malignancies of blood cells ( and
) a bone marrow biopsy is used in staging the disease. The
procedure involves taking a core of using a trabecular
bone , using a trephine and then aspirating material.
LUNGS Biopsies of the lungs can be performed in a variety of ways
depending on the location.
PROSTATE
Forms of prostate biopsy include transrectal
biopsy and transurethral biopsy
NERVOUS
SYSTEM
Forms include brain biopsy, nerve biopsy, and meningeal
biopsy
Urogenital
system
Forms include renal biopsy, endometrial
biopsy and cervical conization

8. GASTROINTE
STINAL
TRACT
Flexible enables access to the upper and lower ,
such that biopsy of the , and via the mouth and the
, and terminal are commonplace. A variety of
biopsy instruments may be introduced through the
endoscope and the visualized site biopsied. Until
recently, the majority of the small intestine could not
be visualized for biopsy. The double-balloon “push-
pull” technique allows visualization and biopsy of the
entire gastrointestinal tract.Needle core biopsies or
aspirates of the pancreas may be made through the
duodenum or stomach.
Other
Other sites include breast biopsy, lymph
node biopsy, muscle biopsy, and skin biopsy

9. Autopsy
a clinical or academic autopsy is performed to find the medical
cause of death and is used in cases of unknown or uncertain
death, or for research purposes.
also known as a post-mortem examination, necropsy
(particularly as to non-human bodies), autopsia cadaverum, or
obduction
is a highly specialized surgical procedure that consists of a
thorough examination of a corpse to determine the cause and
manner of death and to evaluate any disease or injury that may
be present.
It is usually performed by a specialized medical doctor called a
pathologist.

10. There are four main types of autopsies:
· Medico-Legal Autopsy or
Forensic or coroner's autopsies
seek to find the cause and
manner of death and to identify
the decedent. They are
generally performed, as
prescribed by applicable law,
in cases of violent, suspicious
or sudden deaths, deaths
without medical assistance or
during surgical procedures.
· Clinical or Pathological autopsies are performed to diagnose a
particular disease or for research purposes. They aim to determine,
clarify, or confirm medical diagnoses that remained unknown or unclear
prior to the patient's death.

11. · Anatomical or
academic autopsies
are performed by
students of anatomy
for study purpose
only.
Virtual or medical
imaging autopsies are
performed utilizing
imaging technology only,
primarily magnetic
resonance imaging (MRI)
and computed tomography
(CT).

12. is an ancient medical specialty that uses operative manual and
instrumental techniques on a patient to investigate and/or treat a
pathological condition such as disease or injury
Surgery
≈
help improve bodily function or appearance
or to repair unwanted ruptured areas.
A surgeon is a person who practises surgery.
A surgery can last from minutes to hours, but is typically not an
ongoing or periodic type of treatment.
The term surgery can also refer to the place where surgery is
performed, or simply the office of a physician, dentist, or
veterinarian.

13. Histology Sample Preparation
Prepares tissue specimens for sectioning, staining and diagnosis. The
standard paraffin process (tissue processing) moves specimens through a
series of steps so the soft tissue is supported in a medium that allows
sectioning.
The standard steps are:
Embedding that allows orientation of the
specimen in a “block” that can be sectioned
and is easy to store and handle
Sectioning using a microtome to produce
very thin sections that are placed on a
microscope slide ready for staining.

14. Fixation that preserves the tissue
Processing that dehydrates, clears and infiltrates the
tissue with paraffin wax

15. History of Histopathology
(compound of the Greek words: ἱστός histos "tissue", and -λογία -logia
"science")
the study of the microscopic anatomy of cells and tissues of plants and
animals.
It is commonly performed by examining cells and tissues by sectioning and
staining, followed by examination under a light microscope or electron
microscope
In the 19th century, histology was an academic
discipline in its own right. The 1906 Nobel Prize in
Physiology or Medicine was awarded to
histologistsCamillo Golgi and Santiago Ramon y
Cajal. They had dueling interpretations of the neural
structure of the brain based in differing
interpretations of the same images. Cajal won the
prize for his correct theory and Golgi for the staining
technique he invented to make it possible.
Santiago Ramón y Cajal
in his laboratory

16. Instruments in HISTOPATHOLOGY (principles)
A microtome (from the Greek
mikros, meaning "small", and
temnein, meaning "to cut") is a
tool used to cut extremely thin
slices of material, known as
sections. Important in science,
microtomes are used in
microscopy, allowing for the
preparation of samples for
observation under transmitted
light or electron radiation.
Microtomes use steel, glass, or
diamond blades depending upon
the specimen being sliced and
the desired thickness of the
sections being cut.

17. A freezing microtome is
an instrument used in the
laboratory to section
small delicate materials.
Sectioning is done on a
platform which is frozen
by snowing CO2. The
microtome knife is also
snowed with CO2. In this
type of microtome,
sectioning is done by the
microtome knife moving
towards the material to
be sectioned. For
materials that have
alcohol, it should first be
removed before being
sectioned.

18. A cryostat (from cryo meaning
cold and stat meaning stable) is
a device used to maintain low
cryogenic temperatures of
samples or devices mounted
within the cryostat. Low
temperatures may be maintained
within a cryostat by using
various refrigeration methods,
most commonly using cryogenic
fluid bath such as liquid helium.
Hence it is usually assembled
into a vessel, similar in
construction to a vacuum flask
or Dewar. Cryostats have
numerous applications within
science, engineering, and
medicine.

19. The paraffin Embedding
System allows a
convenient, quick and
careful paraffin embedding
of tissue specimens. The
modular structure and the
standard height of the
working area permit to
combine the two modules
of the embedding Station
so as to meet the needs of
the user.

20. vibrating microtomes (vibratomes) let you
accurately cut tissue without freezing or
embedding.