Principles of tissue diagnosis

Principles of Tissue DiagnosisPrinciples of Tissue Diagnosis

Presented by-

Dr. Fariha HussainIntern DoctorSurgery Unit- 5ShSMCH

Definition of CellDefinition 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

Prokaryote Vs EukaryoteProkaryote Vs Eukaryote

Definition of TissueDefinition 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

Four types of tissueFour types of tissue

Connective TissueConnective Tissue

Connective tissue is a fibrous tissue. It is the most diverse tissue and found

throughout the bodyHas 3 main components: Cells, Fibers,

and Extracellular matrix

Connective TissueConnective 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

Connective TissueConnective Tissue

Functions of connective tissueFunctions of connective tissue

Providing structural framework for the body

Connection of body tissuesStorage of energyProtection of organs

Epithelial TissueEpithelial Tissue

Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands.

Structure of Epithelial TissueStructure 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

Structure of Epithelial TissueStructure 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.

Special types of EpitheliumSpecial 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

Special types of EpitheliumSpecial types of Epithelium

Transitional Epithelium: – found in tissues that stretch– sometimes called the urothelium– almost exclusively found in the bladder,

ureters and urethra

Fig: Keratinized Squamous Epithelium

Muscle TissueMuscle 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

Structure of muscle tissueStructure of muscle tissue

Stucture of smooth muscle Stucture of smooth muscle

Structure of Cardiac muscleStructure of Cardiac muscle

Nervous TissueNervous 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.

Structure of a NeuronStructure of a Neuron

Methods of tissue diagnosisMethods 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

What is a Biopsy?What is a Biopsy?

Biopsy is the removal of tissue for the purpose of diagnostic examination.

Principles and Techniques of Principles and Techniques of BiopsyBiopsy

It is important to develop a systematic approach in evaluating a patient with a lesion

These steps include :These steps include :

A detailed health historyA history of the specific lesionA clinical examinationA radiographic examinationLaboratory investigationsSurgical specimens for histopathologic

evaluation

Medical conditions that Medical conditions that warrant special care include:warrant special care include:CoagulopathiesHypertensionPoorly controlled diabetesImmunocompromised patients

History of the LesionHistory of the Lesion

Questions to AskQuestions to Ask

Duration of the lesionChanges in size and rate of changeChanges in the character of the lesion.

– Lump to ulcer, etcAssociated systemic symptoms:

– fever– nausea– anorexia

More Questions to AskMore Questions to AskPainAbnormal sensationsAnesthesiaA feeling of swellingBad taste or smell DysphagiaSwelling or tenderness of adjacent lymph

nodesCharacter of the pain if present

Clinical ExaminationClinical Examination

The clinical examination should always include when possible:– Inspection– Palpation– Percussion– Auscultation

Clinical EvaluationClinical 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

Radiographic ExaminationRadiographic 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

Indications for BiopsyIndications 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.

Indications for BiopsyIndications 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

Characteristics of lesions that raise the Characteristics of lesions that raise the suspicion of malignancysuspicion 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

Types of BiopsyTypes of Biopsy

Fine neeedle aspiration biopsy/cytology (FNAB or FNAC)

Tru-cut biopsyIncisional biopsy Excisional biopsyCone biopsyWedge biopsyFrozen section biopsy

Fine Needle Aspiration BiopsyFine 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

AspirationAspiration

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.

FNACFNAC

Tru-cut biopsyTru-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

PRINCIPLE OF TRUCUT BIOPSYPRINCIPLE OF TRUCUT BIOPSY

Incisional BiopsyIncisional 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

Incisional BiopsyIncisional 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.

Incisional BiopsyIncisional Biopsy

Excisional BiopsyExcisional 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.

Excisional BiopsyExcisional Biopsy

Technique:– The entire lesion with 2 to 3mm of normal

appearing tissue surrounding the lesion is excised if benign.

Wedge BiopsyWedge Biopsy

An excisional biopsy in which a lesion identified at the time of a surgical procedure is removed, with a wedge of normal surrounding tissue

Wedge BiopsyWedge Biopsy

Cone BiopsyCone 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.

Cervical Cone BiopsyCervical Cone Biopsy

Frozen Section BiopsyFrozen Section BiopsyThis 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.

Frozen Section BiopsyFrozen 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.

Biopsy guidanceBiopsy guidance

Blindly without any guidanceX-ray to see the locationUSG guidedCT guidedMRI guided

Principles of Surgery for Principles of Surgery for BiopsyBiopsy

AnesthesiaAnesthesia

Block anesthesia is preferred to infiltration

When blocks are not possible distant infiltration may be used

Never inject directly into the lesion

Tissue StabilizationTissue Stabilization

Digital stabilizationSpecialized retractors/forcepsRetraction suturesTowel Clips

HemostasisHemostasis

Gauze compresses are usually adequateSuction devices should be avoided

IncisionsIncisions 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.

Handling of the Tissue Handling of the Tissue SpecimenSpecimenDirect handling of the lesion will expose

it to crush injury resulting in alteration the cellular architecture.

Specimen CareSpecimen Care

The specimen should be immediately placed in 10% formalin solution, and be completely immersed.

Margins of the BiopsyMargins of the Biopsy

Margins of the tissue should be identified to orient the pathologist. A silk suture is often adequate.

Biopsy Data SheetBiopsy 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.

Conditions identified with biopsyConditions identified with biopsy

CancerPrecancerous conditions Inflammatory conditionsInfections e.g. TuberculosisAutoimmune disorders e.g. lupus

Biopsy ResultsBiopsy Results

A biopsy is most commonly done to indentify malignancy

Characteristics of Benign and Characteristics of Benign and Malignant neoplasmsMalignant 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

Characteristics of Benign and Characteristics of Benign and Malignant neoplasmsMalignant 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

DIFFERENTIATION AND ANAPLASIADIFFERENTIATION 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

DIFFERENTIATION AND ANAPLASIADIFFERENTIATION 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

Microscopic features of malignancyMicroscopic 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

Microscopic features of Microscopic features of malignancymalignancy 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.

Microscopic features of Microscopic features of malignancymalignancyAngiogenesis - malignant tumours must

form new blood vessels in order to expand locally. Angiogenesis is also important for metastasis.

Normal Vs Malignant tissueNormal Vs Malignant tissue

Normal Vs Malignant tissueNormal Vs Malignant tissue

Normal Vs Malignant CellsNormal 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

Tumour giant cellTumour giant cell

Malignant cells with an osteoclast-type giant cell

Malignant Epithelpoid CellsMalignant Epithelpoid Cells

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.

Biopsy Results: What If ?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