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
Definition of TissueA 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
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
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
Functions of connective tissue Providing structural framework for the body Connection of body tissues Storage of energy Protection of organs
Epithelial TissueEpithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands.
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
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.
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
Special types of Epithelium Transitional Epithelium: – found in tissues that stretch – sometimes called the urothelium – almost exclusively found in the bladder, ureters and urethra
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
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.
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
What is a Biopsy? Biopsy is the removal of tissue for the purpose of diagnostic examination.
Principles and Techniques of Biopsy It is important to develop a systematic approach in evaluating a patient with a lesion
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
Medical conditions thatwarrant special care include: Coagulopathies Hypertension Poorly controlled diabetes Immunocompromised patients
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
More Questions to Ask Pain Abnormal sensations AnesthesiaA feeling of swelling Bad taste or smell Dysphagia Swelling or tenderness of adjacent lymph nodes Character of the pain if present
Clinical Examination The clinical examination should always include when possible: – Inspection – Palpation – Percussion – Auscultation
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
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
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.
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
Characteristics of lesions that raise thesuspicion 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 Biopsy Fine neeedle aspiration biopsy/cytology (FNAB or FNAC) Tru-cut biopsy Incisional biopsy Excisional biopsy Cone biopsy Wedge biopsy Frozen section biopsy
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
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.
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
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
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.
Excisional BiopsyAn 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 Biopsy Technique: – The entire lesion with 2 to 3mm of normal appearing tissue surrounding the lesion is excised if benign.
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
Cone BiopsyA 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.
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.
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.
Biopsy guidance Blindly without any guidance X-ray to see the location USG guided CT guided MRI guided
Hemostasis Gauze compresses are usually adequate Suction devices should be avoided
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.
Handling of the TissueSpecimen Direct handling of the lesion will expose it to crush injury resulting in alteration the cellular architecture.
Specimen Care Thespecimen should be immediately placed in 10% formalin solution, and be completely immersed.
Margins of the Biopsy Margins of the tissue should be identified to orient the pathologist. A silk suture is often adequate.
Biopsy Data SheetA 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 biopsy Cancer Precancerous conditions Inflammatory conditions Infections e.g. Tuberculosis Autoimmune disorders e.g. lupus
Biopsy ResultsA biopsy is most commonly done to indentify malignancy
Characteristics of Benign andMalignant 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 andMalignant 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 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 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 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 ofmalignancy 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 ofmalignancy Angiogenesis - malignant tumours must form new blood vessels in order to expand locally. Angiogenesis is also important for metastasis.
Normal Vs Malignant CellsA. Normal Papanicolaou smear from the uterine cervix. Large, flat cells with smallnuclei. B, Abnormal smear containing a sheet of malignant cells with largehyperchromatic nuclei. There is nuclear pleomorphism, and one cell is in mitosis
Tumour giant cellMalignant cells with an osteoclast-type giant cell
Immunohistochemical staining : (a) Normal (non-neoplastic) breast tissue; Notestaining in normal ducts. (b) Human breast carcinoma (infiltrating ductal carcinoma);formalin-fixed, paraffin-embedded tissue. Note strong membranous staining in breastcancer. (c) Normal (non-neoplastic) breast tissue; frozen tissue. Note staining in normalducts. (d) Human breast carcinoma; frozen tissue. Note staining of invasive breastcarcinoma.
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