First Term Revision AIU 2024 PDF

First term practical revision Introduction Methods of studying morphologic alterations Autopsy Surgical Biopsy Tru cut needle Endoscopic Fine needle aspiration Cytology Exfoliative cytology...

First term practical revision Introduction Methods of studying morphologic alterations Autopsy Surgical Biopsy Tru cut needle Endoscopic Fine needle aspiration Cytology Exfoliative cytology 4  Methods of studying morphologic alterations Autopsy It is the study of organs and tissues removed from the dead body for verification of the clinical diagnosis of the disease. 5 Necropsy (autopsy) 6  Biopsy is the pathological study of tissue or organs removed during life for diagnostic purposes. 7  8 Biopsy According to the instrument used to obtain them Biopsy might be: Surgical Tru cut needle Endoscopic  Biopsy a. A surgical biopsy: Taken by a scalpel or knife. It is either an 1. Incision biopsy when only a portion of the lesion is sampled or 2. Excision biopsy when the entire lesion is removed usually with a rim of normal tissue. The procedure serves both diagnostic and therapeutic function. 9  Incision biopsy when only a portion of the lesion is sampled Excision biopsy when the entire lesion is removed usually with a rim of normal tissue. The procedure serves both diagnostic and therapeutic function. 10 b. Tru-cut needle biopsy: When taken by a needle 11  c. Endoscopic biopsy: When taken through endoscopy. 12 Cytology is the study of individual cells in detail. 13  Cytology a. Fine needle aspiration. cells sucked out of a solid tissue using a thin needle attached to a syringe. 14  Cytology a. Fine needle aspiration. cells sucked out of a solid tissue using a thin needle attached to a syringe. 15  Cytology b. Exfoliative cytology: Studying cells shed from, or scraped or brushed off an epithelial surface e.g. urine, sputum, cervical smear. 16  Cytology b. Exfoliative cytology: Studying cells shed from, or scraped or brushed off an epithelial surface e.g. urine, sputum, cervical smear. 17  STEP 1 : GROSSING Gross Examination Description: Specimen weight & measurement (approx) Consistency Photo * Cut section STEP 1 : GROSSING 19  STEP 1 : GROSSING Size Number External surface Cut section Unilocular or multilocular Inner surface content 20 Cell Injury CLOUDY SWELLING  Cloudy swelling kidney Gross Picture: The organ is enlarged with increase in weight. It is pale in color. Cloudy swelling kidney: Gross  Cloudy swelling kidney Microscopic Picture: The cells are swollen the cytoplasm is granular and cloudy due to swollen mitochondria. The nucleus is not affected. Cloudy swelling kidney  Cloudy swelling kidney Microscopic Picture: Normal Cloudy swelling FATTY CHANGE Fatty liver: Gross Picture  Fatty liver: Gross Picture Enlarged liver Increased weight. Yellowish in color. Soft in consistency. Greasy in touch.  Fatty Liver Normal Fatty Fatty Liver: Gross Picture  Later on, these vacuoles coalesce There are small fat vacuoles forming large spaces that displace around the nucleus. the nucleus to the periphery of the cell.  There are small fat vacuoles around the nucleus. Fatty Liver: microscopic Later on, these vacuoles coalesce forming large spaces that displace the nucleus to the periphery of the cell.  There are small fat vacuoles around the nucleus. Fatty Liver: microscopic Later on, these vacuoles coalesce forming large spaces that displace the nucleus to the periphery of the cell. Calcification  Dystrophic calcification Morphology: Gross picture: The calcified tissue appears opaque white and hard in consistency. The cut surface is finely granular.  Dystrophic calcification Morphology: Microscopic picture: Calcium stains dark blue with haematoxylin. Dystrophic calcification in a blood vesselDark bluish patches of calcification within the blood vessel wall Dystrophic calcification in a blood vessel Metastatic calcification Pigments Types of Pigments in our body Pigments Exogenous Endogenous Inhalation Non –HB Melanin Anthracosis derived Lipofuscin Inoculation HB-dervied Hemosiderin Bilirubin tattoo  Tarry black spots within the 1-Anthracosis lung parenchyma Anthracosis lung: Gross  1-Anthracosis Anthracosis lung: microscopic nthracosis Macrophages laden with tarry black carbon particles 1-Anthracosis Anthracosis lung:microscopic Macrophages laden with tarry black carbon particles 2- Tattooing They are phagocytosed by dermal macrophages in which pigments reside for life. Derma macrophages laden with tattoo pigment  3- Melanin Compound naevus showing clusters of benign naevus cells in the dermis as well as in lower epidermis. These cells contain coarse, granular, brown-black melanin pigment 4- Lipofuscin Brown pigments present in the cytoplasm, around the nucleus. (perinuclear) 4- Lipofuscin Brown pigments present in the cytoplasm, around the nucleus. (perinuclear)  Hemosiderin pigment inside 5- hemosiderin alveolar macrophages in chronic venous congestion of the lung (endogenous pigment) Hemosiderin pigment inside alveolar macrophages in chronic venous congestion of the lung (endogenous pigment)  Golden brown “Hemosiderin pigment” inside alveolar 5- hemosiderin macrophages in chronic venous congestion of the lung (endogenous pigment) AMYLOIDOSIS  Amyloidosis By H&E staining under light microscopy: Amyloid appears as extracellular, homogeneous, structureless and eosinophilic hyaline material.  Amyloidosis By H&E staining under light microscopy: Amyloid appears as extracellular, homogeneous, structureless and eosinophilic hyaline material.  Amyloidosis Congo red staining : Salmon pink and shows apple-green birefringence on polarizing microscopy. Renal amyloidosis in BVs and glomeruli , congo red stain  Amyloidosis Congo red staining : Salmon pink and shows apple-green birefringence on polarizing microscopy.  Amyloidosis Congo red staining : Salmon pink and shows apple-green birefringence on polarizing microscopy. Types of necrosis Morphologic types of necrosis Coagulative Liquefactive Caseous Gummatous Fat 1- COAGULATIVE NECROSIS  1. Coagulative necrosis Mechanism: – Denaturation and coagulation of cytoplasmic proteins – Denaturation of proteolytic enzymes so proteolysis and digestion of dead cells is blocked. Enzymatic digestion of dead cells Coagulation (denaturation of proteins) Lysis of cells Coagulation  1. Coagulative necrosis Site: Solid organs as heart, kidney, spleen, adrenals …etc. Gross: the necrotic area appears ▪ opaque ▪ it is triangular, cone, or fan-shaped ▪ the base to the outside ▪ the apex pointing to the closed vessel. ▪ It is firm & raised above the surface. Coagulative necrosis in SPLEEN Coagulative necrosis in spleen Coagulative necrosis in spleen Coagulative necrosis in kidney Renal infarct 2- LIQUEFACTIVE NECROSIS  2) Liquefactive necrosis Pathogenesis: – Rapid liquefaction of the cytoplasm by Lysosomal enzymes Causes: – Brain and spinal cord – Suppurative inflammation as Abscess Coagulation Enzymatic digestion of (denaturation of proteins) dead cells Lysis of Coagulation cells 3- CASEOUS NECROSIS  3. Caseous necrosis Pathogenesis: It is a combination of coagulative and liquefactive necrosis Shape: friable cheesy material Cause: tuberculosis Enzymatic digestion of Coagulation dead cells (denaturation of proteins) Lysis of Coagulation cells Gangrene DRY GANGRENE  Dry gangrene Grossly: The gangrenous part appears dry, black, shrunken and mummified. It starts at the tips of phalanges and ascends up the limb and stops where an adequate blood supply is reached. A line of Demarcation is seen between the healthy and dead tissue A line of separation → (auto removal or auto amputation).  Dry gangrene dry, black, shrunken and mummified. Line of demarcation  dry, black, shrunken and mummified. Line of demarcation Line of separation  dry, black, shrunken and mummified. Line of demarcation  dry, black, shrunken and mummified. Line of demarcation  dry, black, shrunken and mummified. Line of demarcation WET GANGRENE  2)Wet Gangrene: (Moist gangrene) Grossly: The gangrenous part is black, swollen and foul smelling. There are no lines of demarcation or separation between healthy and dead tissues.  2)Wet Gangrene: (Moist gangrene) There are no lines of demarcation or separation between healthy and black, dead tissues. swollen and foul smelling. Wet Gangrene of small intestine  There are no lines of demarcation or separation between healthy and dead tissues. black, swollen and foul smelling. Wet Gangrene of small intestine  There are no lines of demarcation or separation between healthy and dead tissues. black, swollen and foul smelling. Wet Gangrene of small intestine  There are no lines of demarcation black, or separation between healthy and swollen and dead tissues. foul smelling. Wet Gangrene of small intestine Inflammation  Inflammation Acute Chronic Specific Suppurative Non suppurative Non specific (Granuloma) Localized Diffuse -Serous -Catarrhal -Hemorragic Boil -Membranous Abscess Stye Carbuncle (furuncle) -Cellulitis - -Phlegmonous Gangrenous……etc -Supp. In a body cavity -Empyema Acute inflammation Non suppurative  Acute inflammation Skin blister (from serum) Non suppurative Burn Mechanical irritation Serous Inflammation Burn blister  Acute inflammation Fibrinous inflammation Inflammation Non suppurative Fibrinous pericarditis (Bread and Butter) Fibrin meshwork entangling inflammatory cells Mainly neutrophils  Acute inflammation Non suppurative Fibrinous exudate : Microscopically: There is fibrin network entangling inflammatory cells mainly neutrophils. i-4 Fibrin meshwork entangling inflammatory cells Mainly neutrophils  Acute inflammation Non suppurative fibrinous Inflammation: describe Grossly: The fibrinous exudate appears as a Fibrinous pinkish yellow mantle, pericarditis covering the serous lining (Bread and Butter) resembling bread and butter appearance.  Acute inflammation Non suppurative Pseudo-membranous inflammation False membrane False membrane : (fibrinopurulent exudate combined with necrotic - Yellowish white, creamy membrane mucosa.) - Tightly adherent - Bleeds easily Microscopically Fibrin Necrotic debris Neutrophils Red cells Bacillary Dysentry  Acute inflammation Pseudo-membranous inflammation Non suppurative False membrane Diphtheria (fibrinopurulent exudate combined with necrotic False membrane : mucosa.) - Yellowish white, creamy membrane -Tightly adherent -Bleeds easily Diphtheria  Acute inflammation Non suppurative Hemorrhagic inflammation A severe form of inflammation associated with hemorrhage  Acute inflammation Non suppurative Allergic Increased number of eosinophils Acute inflammation Suppurative  Acute inflammation Suppurative PUS (suppuration) Characters of pus: 1. It appears as a thick 2. turbid 3. Yellow 4. odorless 5. alkaline fluid. 6. It does not clot on standing because its fibrinogen content is destroyed by the proteolytic enzymes.  Acute inflammation Suppurative inflammation Suppurative Pus (Purulent exudate ) Components? i-7  Acute inflammation Suppurative inflammation Suppurative Pus (Purulent exudate ) Dead and dying neutrophils ( pus cells) Dead and living bacteria + their toxins Plasma proteins i-7 Liquified tissue debris All suspended in exudate Types of suppurative (purulent) inflammation 1. Localized 2. Diffuse Abscess Cellulitis Special types of Phlegmonous inflammation abscesses Diffuse suppuration in a 1. Stye body cavity 2. Boil (furuncle) Collection of pus in the 3. Carbuncle lumen of an organ (empyema)  Explain the difference between 2 pictures ? Organism ? Organism  Staph aureus Strept hemolyticus Streptokinase (fibrinolysin): staph releases coagulase Dissolves and prevents fibrin enzyme leading to formation. localization of infection Hyaluronidase enzyme: breaks (Therefore localized cavity down tissue cement substance helping spread of bacteria and its toxins. Acute inflammation Suppurative Localized  Acute inflammation Suppurative Localized Abscess Cavity filled with pus Surrounded by red zone  Acute inflammation Suppurative Localized Abscess Localized supp. inflammation Cavity containing pus A liver abscess (localized area containing pus) i-6  Acute inflammation Suppurative Localized Microscopic morphology of the abscess 1. a central largely necrotic area composed of pus 2. rimmed by a layer of preserved (living neutrophils) 3. a surrounding zone of dilated vessels and fibroblastic proliferation (pyogenic membrane) which indicates early repair. Acute inflammation Suppurative Localized Abscess  Acute inflammation Suppurative Localized Lung abscess  Acute inflammation Special types of abscess Suppurative Localized Boil - Furuncle Small abscess Hair follicle or sebaceous gland Face, axilla, back, neck Stye Abscess in eyelid Related to eyelashes  Acute inflammation Special types of abscess Suppurative Localized Carbuncle Multilocular abscess Discharge through multiple sinuses In skin of back of neck + subcutaneous tissue mainly nape Diabetics  Acute inflammation Special types of abscess Suppurative Localized Carbuncle Multilocular abscess Discharge through multiple sinuses In skin of back of neck + subcutaneous tissue mainly nape Diabetics Acute inflammation Suppurative Diffuse Types of diffuse suppurative (purulent) inflammation Diffuse Cellulitis Phlegmonous inflammation Diffuse suppuration in a body cavity Collection of pus in the lumen of an organ (empyema)  Acute inflammation Cellulitis Sites: Suppurative Diffuse the suppurative inflammation spreads in the connective tissue planes leading to diffuse suppuration loose connective tissue as subcutaneous tissue Areolar tissue of the orbit  Acute inflammation Suppurative Diffuse 2. Phlegmonous inflammation Acute diffuse suppurative inflammation of a hollow organ e.g. phlegmonous appendicitis. Phlegmonous appendicitis Transmural infiltration by neutrophils  Acute inflammation Suppurative Diffuse Phlegmonous Inflammation Throughout whole thickness of hollow organ The organ is swollen edematous, red and hot with foci of suppuration on serosal surface (green arrows) Phlegmonous appendicitis  Acute inflammation Suppurative Diffuse Acute suppurative meningitis Meninges are separated by a suppurative exudate 1. It is thick 2. turbid 3. Yellow. 4. odorless 5. It does not clot on standing  Acute inflammation Suppurative Diffuse Diffuse spreading suppurative inflammation In body cavities Pericarditis Acute suppurative meningitis Peritonitis  Acute inflammation Suppurative Diffuse Diffuse spreading suppurative inflammation Acute suppurative Pericarditis Acute suppurative Peritonitis  Acute inflammation Suppurative Diffuse 4. Empyema Collection of pus in the lumen of an organ: e.g Empyema of gall bladder, Or body cavity e.g pleura empyema Empyema of gall bladder  Outcomes (sequelae) of Acute inflammation Non suppurative Suppurative Healing by complete resolution Healing by complete resolution Healing by scarring or fibrosis Healing by scarring or fibrosis Excessive scar formation Progression to chronic Progression to chronic inflammation inflammation Superadded suppuration Superadded suppuration Spread Spread  Superadded suppuration: It occurs due to superadded infection with pyogenic microorganisms. Superadded suppuration  Healing by scarring or fibrosis Healing by scar formation  Outcomes (sequels) of Acute inflammation Suppurative Non suppurative Healing by complete resolution Drainage Healing by complete resolution Healing by scarring or fibrosis Healing by scarring or fibrosis Excessive scar formation Progression to chronic Progression to chronic inflammation inflammation Superadded suppuration Superadded suppuration Complications Spread Spread  Fate of abscess 1. Drainage Click for larger image At least resistance Contents Discharge of contents under Pointing Collapse of cyst, pressure Fibrosis Spontaneous or Surgical  Abscess Fate 2. Fibrous cavity Cyst Large abscess - Walled off - Pus inspissated +/ - Calcified Complications of acute suppurative inflammation  1. Sinus Track Blind ended From cavity to surface  Abscess 2.Fistula Track open at both ends Between 2 surfaces 3. Ulceration 4.Chronic abscess Thick fibrous wall pus Excessive scar tissue formation (keloid) Healing by fibrous tissue formation e.g. healing of diffuse spreading suppurative pericarditis is associated with thick fibrous tissue adhesions leading to adhesive or constrictive pericarditis  Bacteremia Toxemia Septicemia Pyemia transient circulation of virulent, circulation of toxins in the pus in blood bacteria in the blood. multiplying blood, microorganisms arrest in exogenous or different No toxins. endogenous + their toxins in organs the blood. causing new No manifest. manifest. Severe multiple small Manifestations pyemic abscesses  Pyemic abscesses in a kidney Grossly: Pyemic abscesses are multiple, small, rounded abscesses. Surrounded by red zone  Pyemic abscesses in a kidney Grossly: Pyemic abscesses are multiple, small, rounded abscesses. Surrounded by red zone Chronic inflammation Chronic inflammation Classification 1. Nonspecific No specific hallmark Diffuse accumulation of Macrophages (histiocytes) Lymphocytes Fibroblasts Thick walled blood vessels. Chronic inflammation Classification 2. Specific Silica We find a specific lesion to denote the etiology Granulomatous inflammation: Tuberculosis  Inflammation Acute Inflammatory cells Neutrophils (polymorphs) Chronic inflammatory cells 1. Macrophages: 2. Lymphocytes 3. Plasma cells 4. Eosinophils 5. Fibroblasts Healing and repair  Healing by ? LABILE STABLE REGENERATION REGENERATION 2 1 LABILE REGENERATION FIBROSIS 3 PERMENENT 4 FIBROSIS STABLE PERMANANT FIBROSIS 6 REGENERATION FIBROSIS 5  Healing by ? STABLE REGENERATION LABILE FIBROSIS 1 REGENERATION 2 STABLE PERMANANT 3 REGENERATION FIBROSIS FIBROSIS 4  Types of skin injury : Incision ( cut ): Wounds with Abrasion or scrape : superficial epithelium full thickness ( epidermal only ; restoration epidermis + dermis ) defects : large complete with minimal loss of gaping germinal layer on wounds both sides Regeneration First intention Second intention  1. Healing by first intention (primary union) the simplest example It is healing of 1. a clean incised surgical wound 2. uninfected 3. the two edges of the wound are approximated together by surgical sutures. 4. minimal tissue loss. 1- Healing by first intention (primary union) 158 159 2- Healing by second intention (Secondary union): Wide gap Marked tissue loss &necrosis Sepsis burns large abscess large infected wounds 2- Healing by second intention (Secondary union): 161 162 Steps of healing process  Steps of scar tissue formation 1)Inflammatory response by neutrophils and macrophages to remove damaged and dead tissue 2)Proliferation of parenchymal and connective tissue cells 3) Angiogenesis and granulation tissue 4) Fibrosis and Collagen deposition 5) Tissue remodelling 6) Wound contraction  1. Angiogenesis: it is the formation of newly formed blood vessels at the site of injury from preexisting vessels (neovascularization). Name the lesion and describe this picture Granulation tissue Edematous Red velvety oozing  Granulation tissue Defined as a highly vascularized connective tissue Composed of : 1. Newly formed capillaries 2. Proliferating fibroblasts 3. Inflammatory cells in an oedematous stroma 167 Granulation tissue -Newly formed capillaries -Proliferating fibroblasts -Inflammatory cells in an oedematous stroma  Fibrosis (fibroplasia) From the 3rd -5Th day, fibroblasts lay down collagen fibers, this continues for several weeks associated with obliteration of capillaries. The scar formed is composed of largely inactive –spindle shaped fibroblasts, –dense collagen,  Complications of wound healing: 1. Keloid 2. Exuberant granulation or proud flesh 3. Wound dehiscence (split-apart/ rupture of a wound 4. Contracture with distortion 5. Wounds can ulcerate 6. Weak scars 7. Painful scar 8. keratin-filled epidermal cyst. 9. Neoplasia is a rare complication of healing.  Keloid prominent raised scars due to excessive accumulation of collagen ? a heritable predisposition to keloid formation. The condition is more common in blacks. Keloid Keloid - Stretched overlying epidermis devoid of skin appendages. - The dermis features bundles of thick dense collagen fibres. Keloid Scars Keloid Exuberant granulation or proud flesh: Excessive granulation tissue may protrude above the level of the surrounding skin, thus hindering re-epithelialization. Wound dehiscence (split-apart/ rupture of a wound) is opening of a healing or partially healed wound due to mechanical factors, infection or ischemic necrosis of the sutured edges.  Contracture with distortion due to thickening and shortening of collagen bundles may cause serious cosmetic and functional disability particularly in deep and extensive skin burns around the joints if muscles are seriously damaged.  Wounds can ulcerate due to inadequate vascularization during healing e.g. lower limb wounds in patients with atherosclerotic peripheral vascular disease or in areas devoid of sensation (e.g. in diabetic peripheral neuropathy). Weak scars with possible development of incisional hernia.  Keratinous cysts ( epidermal inclusion cysts) Implantation of epidermal cells in the wound giving rise to keratin-filled epidermal cyst.  181 Malignant ulcer Hemodynamics Hyperemia  Hyperemia Active Named Hyperemia Bright red hypremic conjunctiva due to conjunctivitis  Hyperemia Active Named Hyperemia Bright red hypremic inflamed finger  Hyperemia Active Named Hyperemia Bright red hypremic face  Dark red- swollen - venous congestion lung wet Normal Congested venous congestion lung Dark red- swollen – wet  Long standing case Chronic venous congestion lung Dark red- swollen – firm = brown induration of the lung Chronic venous congestion lung Congested capillaries in alveolar wall Alveoli Alveoli Alveoli Hear failure cells Chronic venous congestion lung Congested capillaries in alveolar wall Hear failure cells  Chronic venous congestion liver Large – tense capsule – smooth CS is mottled Yellow and dark red areas As nutmeg  Chronic venous congestion liver CS is mottled Yellow and dark red areas As nutmeg  Chronic venous congestion liver CS is mottled Yellow and dark red areas As nutmeg Chronic venous congestion liver Infarction  Infarction Infarction of spleen:  Infarction Infarction of spleen:  Infarction Infarction Infarction of kidney:  Infarction Infarction Infarction of kidney:  Infarction Infarction Infarction of heart: Myocardial infarcts are irregular and determined by the distribution of the occluded vessels and the state of the collateral circulation.  Infarction Infarction Infarction of heart: Myocardial infarcts are irregular and determined by the distribution of the occluded vessels and the state of the collateral circulation.  Infarction Infarction Infarction of heart: Myocardial infarcts are irregular and determined by the distribution of the occluded vessels and the state of the collateral circulation. Infarction Infarction Infarction Infarction of brain : Cerebral infarcts are irregular and determined by the distribution of the occluded vessels and the state of the collateral circulation. Its cystic or cavity like Due to liquefaction of necrotic tissue Infarction Infarction Infarction Infarction of brain : Cerebral infarcts are irregular and determined by the distribution of the occluded vessels and the state of the collateral circulation. Infarction Infarction Infarction Infarction of brain : Cerebral infarcts are irregular and determined by the distribution of the occluded vessels and the state of the collateral circulation. Infarction Infarction Infarction Infarction of lung : heamorrhagic/red infarction Infarction Infarction Infarction Infarction of lung : heamorrhagic/red infarction Infarction Infarction Infarction Infarction of intestine : heamorrhagic/red infarction complicated by gangrene Infarction Infarction Infarction Infarction of intestine : heamorrhagic/red infarction complicated by gangrene Haemorrhage Heamopericardium Heart Hemorrhage in pericardial cavity Heamopericardium Heart Hemorrhage in pericardial cavity  Hemorrhage Heamorrhage in the interstitial tissue: Internal Depend on amount purpura Hematoma a Petechiae, minute Ecchymosis, those grossly visible hemorrhagic spots < larger than 1mm accumulation of 1mm (pin's head) blood in the tissue usually of capillary forming a mass. origin  Hemorrhage Heamorrhage in the interstitial tissue: Internal Depend on amount Hematoma is a Petechiae, minute Ecchymosis, those grossly visible hemorrhagic spots < larger than 1mm accumulation of 1mm (pin's head) blood in the tissue usually of capillary forming a tumor- origin like mass.  Interstitial hemorrhage Ecchymosis Petechiae Hematoma  Interstitial hemorrhage Hematoma Ecchymosis Petechiae Thrombosis  Thrombosis Arteries Common on top of atheromatous plaque/atheroma or on top of aneurysm Thrombosis Thrombus Arteries Atherosclerosis of aorta showing multiple atheroma with thrombosis on top of them Yellow atheromas CAUSE: Endothelial injury Thrombosis Thrombus Arteries Atherosclerosis of aorta showing multiple atheroma with thrombosis on top of them Yellow atheromas CAUSE: Endothelial injury  Thrombosis Thrombus Arteries Part of aorta showing aneurysm with a thrombus in the lumen Aneurysm CAUSE: Endothelial injury and Abnormal blood flow  Thrombosis Thrombus Arteries Part of aorta showing aneurysm with a thrombus in the lumen Aneurysm CAUSE: Endothelial injury and Abnormal blood flow  Thrombosis Lines of Zahn : Characteristic laminations within the thrombus due to alternating layers of: 1. Platelets and fibrin (pale) 2. Fibrin containing RBCs & leukocytes (red) CAUSE: Endothelial injury and Abnormal blood flow  Thrombosis Veins Common due to stasis (usually in deep veins of the legs Thrombus CAUSE: Abnormal blood flow  Thrombosis Veins Common due to stasis (usually in deep veins of the legs Thrombus CAUSE: Abnormal blood flow  Thrombosis Heart Thrombosis on top of myocardial infarction Thrombus CAUSE: Endothelial injury  Thrombosis Heart Thrombosis on top of myocardial infarction Thrombus CAUSE: Endothelial injury  Thrombosis Heart Thrombosis on top of myocardial infarction Thrombus CAUSE: Endothelial injury  Thrombosis Lines of Zahn : Characteristic laminations within the thrombus due to alternating layers of: 1. Platelets (pale) 2. Fibrin containing RBCs & leukocytes (red)  Thrombosis Lines of Zahn : Thrombus with lines of zahn  Thrombosis Lines of Zahn : Thrombus with lines of zahn Thank you BY: D R M AR A M A L LA M M ALL AM@A IU.EDU.EG