3. Definition of Cell
Cell : The cell is the basic structural and
functional unit of all known living
organisms. It is the smallest unit of life
that is classified as a living thing.
There are two basic types of cell :
– Prokaryotic cell
– Eukaryotic cell
5. Definition of Tissue
A tissue is an aggregation of cells, not
necessarily identical, but from the same
origin, that together carry out a specific
function.
Animal tissues can be grouped into four basic
types: 1. Connective tissue
2. Muscle tissue
3. Nervous tissue
4. Epithelial tissue
7. Connective Tissue
Connective tissue is a fibrous tissue.
It is the most diverse tissue and found
throughout the body
Has 3 main components: Cells, Fibers,
and Extracellular matrix
8. Connective Tissue
Connective tissue makes up a variety of physical
structures including:
– tendons
– the connective framework of fibers in muscles
– capsules and ligaments around joints
– cartilage
– bone
– adipose tissue
– blood and lymphatic tissue
10. Functions of connective tissue
Providing structural framework for the
body
Connection of body tissues
Storage of energy
Protection of organs
12. Structure of Epithelial Tissue
Cells in epithelium are very densely
packed together like bricks in a wall,
leaving very little intercellular space
The cells form continuous sheets which
are attached to each other at many
locations by tight junctions
13. Structure of Epithelial Tissue
All epithelial cells rest on a basement
membrane, which acts as a scaffolding on
which epithelium can grow.
Cell junctions are especially abundant in
epithelial tissues. They consist of protein
complexes that provide contact
– between neighbouring cells
– between a cell and the extracellular matrix or
– control the paracellular transport.
14.
15. Special types of Epithelium
Pseudostratified columnar epithelium: It is a
type of epithelium that, though comprising only a
single layer of cells, has its cell nuclei positioned
in a manner suggestive of stratified epithelia.
Keratinized Epithelium:
– most apical layers (exterior) of cells are dead and lose
their nucleus and cytoplasm
– contain a tough, resistant protein called keratin
16. Special types of Epithelium
Transitional Epithelium:
– found in tissues that stretch
– sometimes called the urothelium
– almost exclusively found in the bladder,
ureters and urethra
20. Muscle Tissue
Muscle cells form the active contractile
tissue of the body known as muscle tissue
Muscle tissue is separated into three
distinct categories:
– visceral or smooth muscle
– skeletal muscle
– cardiac muscle
24. Nervous Tissue
Nervous tissue is the main component of the
nervous system - the brain, spinal cord, and
nerves-which regulates and controls body
functions.
It is composed of neurons, which transmit
impulses, and the neuroglia cells, which assist
propagation of the nerve impulse and
provide nutrients to the neuron.
26. Methods of tissue diagnosis
Examination of tissues starts with
surgery, biopsy, or autopsy
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
27. What is a Biopsy?
Biopsy
is the removal of tissue for the
purpose of diagnostic examination.
28. Principles and Techniques of
Biopsy
It is important to develop a systematic
approach in evaluating a patient with a
lesion
29. These steps include :
A detailed health history
A history of the specific lesion
A clinical examination
A radiographic examination
Laboratory investigations
Surgical specimens for histopathologic
evaluation
30. Medical conditions that
warrant special care include:
Coagulopathies
Hypertension
Poorly
controlled diabetes
Immunocompromised patients
32. Questions to Ask
Duration of the lesion
Changes in size and rate of change
Changes in the character of the lesion.
– Lump to ulcer, etc
Associated systemic symptoms:
– fever
– nausea
– anorexia
33. More Questions to Ask
Pain
Abnormal sensations
Anesthesia
A feeling of swelling
Bad taste or smell
Dysphagia
Swelling or tenderness of adjacent lymph
nodes
Character of the pain if present
34. Clinical Examination
The clinical examination should always
include when possible:
– Inspection
– Palpation
– Percussion
– Auscultation
35. Clinical Evaluation
The anatomic location of the lesion/mass
The physical character of the lesion/mass
The size and shape of the lesion/mass
Single vs. multiple lesions
The surface of the lesion
The color of the lesion
The sharpness of the boundaries of the lesion
The consistency of the lesion to palpation
Presence of pulsation
Lymph node examination
36. Radiographic Examination
The radiographic appearance may provide
clues that will help determine the nature of the
lesion.
A radiolucency with sharp borders will often be
a cyst
A ragged radiolucency will often be a more
aggressive lesion
Radiopaque dyes and instruments can help
differentiate normal anatomy
37. Indications for Biopsy
Any lesion that persists for more than 2 weeks
with no apparent etiologic basis
Any inflammatory lesion that does not respond
to local treatment after 10 to 14 days.
Persistent hyperkeratotic changes in surface
tissues.
Any persistent tumescence (swelling) either
visible or palpable beneath relatively normal
tissue.
38. Indications for Biopsy
Inflammatory changes of unknown cause that
persist for long periods
Lesion that interfere with local function
Bone lesions not specifically identified by
clinical and radiographic findings
Any lesion that has the characteristics of
malignancy
39. Characteristics of lesions that raise the
suspicion of malignancy
Erythroplasia- lesion is totally red or has a speckled red
appearance.
Ulceration- lesion is ulcerated or presents as an ulcer.
Duration- lesion has persisted for more than two weeks.
Growth rate- lesion exhibits rapid growth
Bleeding- lesion bleeds on gentle manipulation
Induration- lesion and surrounding tissue is firm to the
touch
Fixation- lesion feels attached to adjacent structures
41. Fine Needle Aspiration Biopsy
Aspiration biopsy is the use of a needle and syringe
to penetrate a lesion for aspiration of its contents.
Indications:
– To determine the presense of fluid within a lesion
– The type of fluid within a lesion
– When exploration of an intraosseous lesion is
indicated
42. Aspiration
An 18 gauge needle on a 5 or 10 ml
syringe is inserted into the area under
investigation after anesthesia is obtained.
The syringe is aspirated and the needle
redirected if necessary to find the fluid
cavity.
44. Tru-cut biopsy
The tru-cut biopsy aims to provide the
pathologist with a core of undamaged
tissue from the lesion.
The procedure is performed using a
specially designed needle known as the
Trucut needle
46. Incisional Biopsy
An incisional biopsy is a biopsy that
samples only a particular portion or
representative part of a lesion.
If a lesion is large or has different
characteristics in various locations more
than one area may need to be sampled
47. Incisional Biopsy
Indications:
– Size limitations
– Hazardous location of the lesion
– Great suspicion of malignancy
Technique:
– Representative areas are biopsied in a wedge fashion.
– Margins should extend into normal tissue on the deep
surface.
– Necrotic tissue should be avoided.
– A narrow deep specimen is better than a broad shallow
one.
49. Excisional Biopsy
An excisional biposy implies the complete removal of
the lesion.
Indications:
– Should be employed with small lesions. Less than 1cm
– The lesion on clinical exam appears benign.
– When complete excision with a margin of normal tissue is
possible without mutilation.
50. Excisional Biopsy
Technique:
– The entire lesion with 2 to 3mm of normal
appearing tissue surrounding the lesion is excised
if benign.
51. Wedge Biopsy
Anexcisional biopsy in which a lesion
identified at the time of a surgical
procedure is removed, with a wedge of
normal surrounding tissue
53. Cone Biopsy
A cone biopsy is an extensive form of a cervical
biopsy
It is called a cone biopsy because a cone-shaped
wedge of tissue is removed from the cervix and
examined under a microscope
A small amount of normal tissue around the
cone-shaped wedge of abnormal tissue is also
removed so that a margin free of abnormal
cells is left in the cervix.
55. Frozen Section Biopsy
This technique allows examining
histologic sections within a few minutes
of removing the specimen from the
patient.
The quality of the tissue sections is not as
good as those of the permanent section.
Commonly done intraoperatively for
quick results.
56. Frozen Section Biopsy
Technique: The tissue is frozen and
sliced thinly using a microtome mounted
in a below-freezing refrigeration device
called the cryostat.
The thin frozen sections are mounted on
a glass slide, fixed immediately in liquid
fixative, stained and examined under
microscope.
57. Biopsy guidance
Blindly without any guidance
X-ray to see the location
USG guided
CT guided
MRI guided
59. Anesthesia
Block anesthesia is preferred to
infiltration
When blocks are not possible distant
infiltration may be used
Never inject directly into the lesion
61. Hemostasis
Gauze compresses are usually adequate
Suction devices should be avoided
62. Incisions
Incisions should be made with a scalpel.
They should be converging
Should extend beyond the suspected depth of the lesion
They should parallel important structures
Margins should include 2 to 3mm of normal appearing
tissue if the lesion is thought to be benign.
5mm or more may be necessary with lesions that appear
malignant, vascular, pigmented, or have diffuse borders.
63. Handling of the Tissue
Specimen
Direct handling of the lesion will expose
it to crush injury resulting in alteration
the cellular architecture.
64. Specimen Care
Thespecimen should be immediately
placed in 10% formalin solution, and be
completely immersed.
65. Margins of the Biopsy
Margins of the tissue should be identified
to orient the pathologist. A silk suture is
often adequate.
66. Biopsy Data Sheet
A biopsy data sheet should be completed
and the specimen immediately labeled.
All pertinent history and descriptions of
the lesion must be conveyed.
67. Conditions identified with biopsy
Cancer
Precancerous conditions
Inflammatory conditions
Infections e.g. Tuberculosis
Autoimmune disorders e.g. lupus
69. Characteristics of Benign and
Malignant neoplasms
In the great majority of instances, the
differentiation of a benign from a malignant
tumor can be made morphologically with
considerable certainty
There are criteria by which benign and
malignant tumors can be differentiated
70. Characteristics of Benign and
Malignant neoplasms
These differences can be discussed under the
following headings:
(1) Differentiation and anaplasia
(2) Rate of growth: Most malignant tumours
are rapidly growing
(3) Local invasion: Malignant tumours may be
locally invasive
(4) Metastasis: Occurs in malignant tumours
71. DIFFERENTIATION AND ANAPLASIA
Differentiation: Differentiation refers to the
extent to which parenchymal cells resemble
comparable normal cells, both
morphologically and functionally
– Well-differentiated tumors are thus composed of
cells resembling the mature normal cells of the
tissue of origin of the neoplasm
– Poorly differentiated or undifferentiated tumors
have primitive-appearing, unspecialized cells
72. DIFFERENTIATION AND ANAPLASIA
Anaplasia: Malignant neoplasms
composed of undifferentiated cells are
said to be anaplastic
Indeed, lack of differentiation, or
anaplasia, is considered a hallmark of
malignant transformation
73. Microscopic features of malignancy
Loss of normal tissue architecture
Increased mitotic rate: Mitoses are rarely seen in
normal tissues. Malignant cells will often have
increased numbers of mitoses
Pleomorphism: Malignant cells may show a
range of shapes and sizes, in contrast to regularly
sized normal cells. The nuclei of malignant cells
are often very large and may contain prominent
nucleioli
74. Microscopic features of
malignancy
Hyperchromatic nuclei: The nuclei of malignant
cells typically stain a much darker colour than their
normal counterparts
High nuclear-cytoplasmic ratio: The nuclei of
malignant cells often take up a large part of the cell
compared with normal cell nuclei
Giant cells: Some malignant cells may coalesce
into so-called giant cells, which might contain the
genetic material of several smaller cells.
75. Microscopic features of
malignancy
Angiogenesis - malignant tumours must
form new blood vessels in order to expand
locally. Angiogenesis is also important for
metastasis.
78. Normal Vs Malignant Cells
A. Normal Papanicolaou smear from the uterine cervix. Large, flat cells with small
nuclei. B, Abnormal smear containing a sheet of malignant cells with large
hyperchromatic nuclei. There is nuclear pleomorphism, and one cell is in mitosis
81. Immunohistochemical staining : (a) Normal (non-neoplastic) breast tissue; Note
staining in normal ducts. (b) Human breast carcinoma (infiltrating ductal carcinoma);
formalin-fixed, paraffin-embedded tissue. Note strong membranous staining in breast
cancer. (c) Normal (non-neoplastic) breast tissue; frozen tissue. Note staining in normal
ducts. (d) Human breast carcinoma; frozen tissue. Note staining of invasive breast
carcinoma.
82. Biopsy Results: What If ?
They don’t corroborate your clinical impression
– Repeat the biopsy
– Determine if the tissue was looked at by an
experienced Pathologist