Issuu on Google+

Prof Dr. Dr Osman A. A Attallah Prof. Visitor Prof. of Pathology D p t t off Patahology, Department P t h l Faculty F lt off Veterinaryy Medicine,, Zagazig g z g University, y, Egypt 2009/2010



Organ: Kidney. Stain: H&E. Lesion:

Cloudy swelling Micro: Mi The epithelial lining of the highly specialized portion of the nephrons (proximal, and distal convoluted tubules and ascending loop of Henle) is swollen. The cytoplasm of the affected epithelium is finely granular and more eosinophilic. The lumina of the affected tubules are narrow (star shape).

(2) Organ: Liver. Stain : H & E. Lesion:

Vacuolar degeneration Micro: The affected hepatic p cells are swollen and present eosinophilic vacuoles (arrows) of variable sizes and illdistinct borders.

(3) g Liver. Organ: Stain : H & E. Lesion:

Hydropic degeneration Micro: The cytoplasm of hepatic cells is completely replaced by pale eosinophilic substance which contains few eosinophilic threads. The hepatic cells are swollen.

(4) Organ: Uterus (endometrium) Stain: H&E. H&E Lesion:

Vesicle formation Micro: S Several l cells ll off the h endometrium d i are replaced by cavities containing pale eosinophilic material (vesicles).

(5) Organ: Fibrous tissue. Stain: H&E. Lesion:

Hyaline degeneration. Micro: The affected fibrous connective tissue appears structurless & more eosinophilic. eosinophilic

(6) Organ: Kidney. Stain : H&E. Lesion:

Hyaline droplets. Micro: The cytoplasm of the affected renal tubules contains large eosinophilic droplets (l). The droplets can be seen better in the highly functioning portions of the nephron by closing the apperture diaphragm.

(7) Organ : Striated muscle. Stain : H&E. L i : Lesion

Hyaline droplets Micro. : Mi The affected muscle fibers are more eosinophilic and usually swollen. { l }. Their longitudinal sections lack both the cross and the longitudinal striations.The cross sections do not show the dots which represent the myofibrils {fields of Cohnheim}.

(8) g Liver Organ: Stain: H&E. Lesion:

Amyloid infiltration. Mi Micro :

Pale eosinophilic structurless substance { 1 } is deposited in the loose connective tissue, under the endothelial lining of the hepatic sinusoids. The hepatic cords appear atrophic (2) with more eosinophilic cytoplasm. Th affected The ff d hepatic h i cells ll andd sinusoids, i id in i addition ddi i to bile bil canaliculi, li li are generally replaced by structurless pale eosinophilic substance {amyloid}.

(9) Organ: Kidney. Stain: H&E. Lesion:

Amyloid A l id infiltration.

Micro.: Pale eosinophilic structurless substaance {amyloid} [2] is deposited in the loose connective tissue, under the endothelial lining of the capillaries of the glomerular tufts, in addition to the walls of the afferent arterioles and b sement membrane basement membr ne of the renal ren l tubules. t b les The glomerular glomer l r tufts t fts are re almost lmost completely replaced by amyloid. The epithelial lining of the renal tubules suffer various retrogressive changes.

(10) Organ: Spleen Stain: H&E. Lesion:

Amyloid i filt ti infiltration (diffuse). Micro: Pale eosinophilic structurless substance ( (amyloid)(l) l id)(l) is i deposited d i d in i the h loose l connective tissue under the endothelial lining of the sinusoids in the red pulp (diffuse amyloidosis or bacon spleen), and frequently the white pulp is involved.

Organ: Kindney. Stain: H&E. Lesion:

Visceral gout. Mi : Micro The affected renal tubules are plugged with radiating(l) g( ) eosinophilic p and basophilic p crystals of sodium urates which caused pressure atrophy and diappearance of the renal epithelium Giant cells of the foreign body type, epithelium. type macrophages and proliferated fibrous tissue partially replaced the renal parenchyma and surrounded the affected renal tubules.

Organ: Joint. Stain: H&E. Lesion:

Articular gout. t Micro: Urates(l) are seen inside the joint capsule, adjacent dj to the h articular i l surface(2) f (2) or in i the connective tissue and muscles around the jjoint. These urates may appear pp either in the form of eosinophilic needle-like crystals or irregular round unstained crystals.

Organ: White fibrous connective tissue. Stain : H&E. Lesion :

Mucoid degeneration. Micro: Numerous rounded, oval or stellate embryonic cells which are widely separated from each other by basophilic structurless substance containingg numerous blood vesselsand lymphatics in addition to cellular processes which criss-cross each other.

Organ: Liver. Stain : H&E. Lesion:

Fatty change. g Micro: The cytoplasm of the affected hepatic cells lls contains nt ins numerous n m r s clear l r vacuoles l s off irregular irr l r sizes siz s with ith sharp borders. Other hepatic cells contain large clear vacuoles which replaced almost all the cytoplasm. The latter appeared as a thin layer under the nuclear membrane containing crescentic nucleus. The affected cell, as a whole, appears as a signet

Organ: Liver. Stain : Oil-red O. Lesion:

Fatty change. h

Micro: The fat is stained dark red(l).

Organ: Liver. Stain : SudanIII. Lesion:

Fatty change. h Micro : The fat is stained orange yellow(l).

Organ: Kidney. Stain : Osmic acid. Lesion:

Fatty change. Mi Micro : Black globules of irregular sizes are seen in the renal cells.

Organ: Lung. Stain : H&E. Lesion: Anthracosis

Micro: Fine black p particles ((carbon particles p or coaldust) appear on the lining of the bronchioles and the air vesicles as well as in the interalveolar sepia, lamina propria of the bronchioles and the regional lymph nodes, either free or inside macrophages.

Organ: Liver. Stain: H&E. Lesion: Hemosiderosis

Micro: Th cytoplasm The l off the h macrophages, h particularly in the portal tracts, contains numerous golden yellow pigments of hemosiderin.

Organ: Liver. Stain : prussian blue. Lesion: Hemosiderosis

Micro: The hemosiderin p pigments g stain blue.

(21) O Organ : Testis T i Stain: H & E. L i Lesion: M l Melanosis i Micro: Numerous macrophages containing brown pi m nts inside pigments insid th their ir cytoplasm t pl sm (melanophores) appear in the interstitial tissue. These pigments may overshadow the structure of the cells which appear as brown masses.

(22) Organ: Brain (meninges). Stain: H&E. Lesion:

Melanosis. Micro: Brownish black melanin pigments are seen mostly inside macrophages (melanophores) in the meninges.

Organ: Lymph node Stain : H&E. Lesion : Dystrophic or local calcification. l ifi i

Micro: Bluish pigments of irregular sizes (l) are seen replacing the lymphoid tissue and among the necrotic tissue of the lymph node. The necrotic tissue appears granular, eosinophilic and structurless (caseous).

Organ: Lymph node. Stain : Von kossa. Lesion : Dystrophic or local calcification. l f

Micro : The calcium salts are stained black(l). black(l)

Organ: Lung. Stain : H & E. Lesion:

Caseous necrosis.

Micro: Both the tissue architecture and the cellular details are lost and replaced by granular eosinophilic and basophilic material (debris) (l). A liline off defense(2) d f (2) surrounds d the h necrotic i tissue.

Organ: Lung. Stain :H&E. Lesion: Liquefactive necrosis.

Micro: The affected alveoli are replaced by structurless b phili Substance basophilic S b t n (pus)(l) (p )(l) surrounded rr nd d b by numerous alive and dead neutrophils(pus-cells) (2)together~vith hyperemic blood vessels. Both cellular details and tissue architecture of the affected pulmonary tissue are lost.

Organ: Adipose tissue. Stain : H & E. Lesion: Fat necrosis.

Micro: The affected adipocytes are mostly replaced by acicular eosinophilic crystals(l).Evidence t l (l) E id off inflammation(2) i fl ti (2) is i present. p t

Organ: Liver. Stain : H & E. Lesion:

Coogulative g necrosis.

Micro: The affected hepatic tissue lost its cellular details with maintenance of tissue architecture(l). A line of demarcation between the necrotic and normal hepatic tissue is evident(2).

Organ: Kidney Stain : H&E. L i Lesion:

Coagulative g necrosis

Micro: The affected tubules lost their cellular details but their tissue architecture is maintained. There is loss of the differential staining of the affected tissue. Karyorrhexis and karylysis are evident.

Organ: Striated muscle. Stain : H&E. Lesion: Coagulative necrosis ((Zenker's necrosis). )

Micro: The affected muscle fibers are more eosinophilic sin phili and nd fr frequently q ntl swollen. s ll n The Th longitudinal sections lost both their cross and longitudinal striations. The cross-sections show no fields of Cohnheim.

Organ: Liver. Stain: H&E. L i Lesion: Pyknosis and karyorrhexis.

Micro: The cytoplasm of some hepatic cells contains scattered fragments of chromatin with disappearance of the nuclear membrane (karyorrhexis).

Organ: Liver. Stain: H&E. Lesion:

Frozen liver.

Micro: Hemolysis of all erythrocytes The destructed hepatic cells are replaced by irregular cavities filled with p pale eosinophilic p structurless material ((l). ) The hepatic cells, surrounding these cavities, appear collapsed(2).

Organ: Liver. Stain : H&E. L i Lesion:

Postmortem change ( (autolysis). l i )

Micro : p y with pale p cytoplasm. y p The picture p of pyknosis, py , Swollen hepatocytes karyorrhexis and karyolysis could be seen. Hemolysis of RBCs is evident. The cellular details of the muscle fibers are lost. Inflammatory cells(2) as macrophages r ph and d neutrophils are usually present together with fibrous tissue proliferation.

Organ: Kidney. Stain: H&E. Lesion: R d infarct. Red i f

Micro: The renal tubules, in the affected area, show coagulative necrosis(l). Numerous erythrocytes are seen among the affected renal tubules. The line of defense(2) ( ) is frequently q y seen between the infarct and the normal area.

Organ: Kidney. Stain: H&E. Lesion: Pale infarct.

Micro: The renal tubules, in the affected area, show coagulative necrosis or may be replaced by granulation tissue or scar. There is a clear line off defense d f between b t the th infarct i f t andd the th normall area.

Organ: Lung. Stain: H&E. Lesion: Passive h hyperemia. i Micro: The interalveolar capillaries p and other blood vessels are congested. The airvesicles contain pale eosinophilic fluid without inflammatory cells (transudate).

Organ: Liver. Stain: H&E. H&E Lesion: Chronic passive congestion. i Micro: The central veins (l), hepatic sinusoids(2) and the other blood vessels essels are re congested. ongested The dilatation dil t tion of the hepatic sinusoids caused pressure atrophy of the hepatic cords. Numerous hemosiderin-pigments are seen inside the kupffer cells and hepatic cells. Fibrous tissue proliferation may be seen around the central vein.

Organ: Lung. Stain: H&E. H&E Lesion: Active hyperemia.

Mi Micro: The interalveolar capillaries (l) which normallyy allow one row of erythrocytes y y to pass are now dilated to permit several rows to pass. The air-vesicles are usually free from exudate during the early stage only. only

Organ: Brain. Brain Stain : H& E. Lesion: Hemorrhage. Hemorrhage

Micro: Extravasated blood is seen in the parcnchymatous nervous tissue(l) and inside the Virchow-Robin spaces(2).

Organ: Uterus (cat). Stain: S a : H & E. Lesion: Hemorrhage. Micro: Extensive hemorrhage(l) in the endometrium, particularly in the deep layer, with cystic dilatation of th uterine the t i glands(2). l d (2)

Organ: Lung Stain : H&E. Lesion: Inflammatory edema.

Micro: The interalveolar capillaries and other blood vessels are congested g (active ( hyperemia). yp ) The air-vesicles are filled with highly eosinophilic finely granular material (albumin), and fine eosinophilic fibers (fibrin). Numerous inflammatory cells, particularly neutrophils are seen inside the alveoli(l).

Organ: Lung. (blood vessel). Stain : H&E. H&E Lesion: Recent thrombus. h b

Micro: Intravascular ggranular eosinophilic p mass is seen in continuation with the intema (l). A few fibrin threads, erythrocytes and neutrophlis may be seen(2).

Organ: Skin (granulation tissue and scar) Stain: H&E. Lesion: Organized g d thrombus o b s

Micro: Granulation tissue and mature fibrous tissue(l) are seen replacing the thrombus inside the affected blood vessel.l

Organ : Anterior mesenteric artery (donkey). Stain : H&E. Lesion: Thrombus.

Micro : Eosinophilic p ggranular mass ((l)) is seen inside d the lumen of the affected blood-vessel and attached to its intema. This mass (thrombus) consists of platlets fibrin platlets, fibrin-threads threads and erythocytes. erythocytes The larvae of strongylus vulgaris(2) are seen embedded in the wall of the affcted blood vessel(3).

Organ: Lung. Stain: H&E. H&E Lesion: Serous inflammation.

Micro: The affected pulmonary tissue presents congested bloodvessels air-vesicles are fill d with filled i h fi fine granular l albumin(l) lb i (l) in i addition to numerous neutrophils.

Organ: Lung. Stain : H & E. Lesion: Catarrhal inflammation.

Micro: The lesion is mainly seen in the respiratory passages. The affected bronchioles(1) ( ) show desquamated q epithelium, thickened lamina propria with congested blood vessels in the presence of inflammatory cells(2). The lumina of the affected bronchioles contain numerous desquamated epithelium and inflammatory cells in addition to bluish mucus(3). The adjacent alveoli show various stages of pneumonia(4).

Organ: Lung. Stain : H & E. Lesion: Fibrinous inflammation.

Micro: The affected pulmonary tissue shows congested blood vessels. The lumina of the affected air-vesicles contain numerous eosinophils, eosinophils fine fibers (fibrin (fibrinthreads) and numerous neutrophils (l).

Organ: Lung. Stain : H & E. Lesion: Serofibrinous i fl mm ti inflammation.

Micro : The criteria of inflammation are present. The predominant constituent of exudate is fibrin together with albumin(1).

(49) Organ: Lung. Stain: H&E. Lesion : Suppurative pp inflammation Micro: The affected pulmonary tissue is replaced by pus (l) (necrotic tissue and pus cells) followed by a zone of congested blood vessels surrounded and g with neutrophils p and fibrin intermingled threads(2). The pus appears as a bluish structurless mass.

(50) Organ: Esophagus. Stain : H & E. L i Lesion: Hemorrhagic inflammation Micro: The affected lamina propria of the esophagus shows congested blood-vessels surrounded with numerous erythrocytes and neutrophils (l).

(51) Organ: Brain. Stain : H & E. Lesion: Lymphocytic inflammation.

Micro: The brain blood-vessels blood vessels are congested. Aggregations of lymphocytes are seen in Virchow-Robin spaces (perivascular cuffing with lymphocytes).

(52) Organ: Liver. Stain : H & E. Lesion:

Lymphocytic y p y hepatitis. Micro: Lymphocytic infiltration) in the portal area. The hepatic cells showed degenerative changes.

(53) Organ: Liver. Stain : H&E. Lesion: Granulomatous hepatitis.

Micro: Focal replacement of the hepatic parenchyma with macrophages (l) surrounding caseated material(2).

(54) Organ: Liver. Stain : H &E. Lesion: Granulomatous hepatitis.

Micro: Focal replacement of the destroyed h hepatic parenchyma h with h macrophages (l), and both Langhan's h ' (2)) and d foreign f body b d giant cells.

(55) Organ: Gingiva. Stain: H&E. H&E Lesion:

Fibrinous inflammation.

Micro: Congested blood vessels are g with numerous seen together leucocytes and fibrin-threads .

(56) Organ: Lung. Stain: H&E. Lesion: Or nized exudate Organized e d te

Micro: The exudate, inside the alveoli is replaced by fibrous connective tissue (fibroblasts and d collagen-fibers) ll fib ) (l). (l)

(57) Organ : Adipose tissue. tissue Stain : H&E. Lesion:


Micro : The affected adipose tissue changes to chondrocytes (1). (1)

(58) Organ: g Lung. g Stain : H & E. Lesion:


Micro: Th pseudostratified The d t tifi d columnar l epithelial lining (l) of the bronchioles i changed is h d tto stratified t tifi d squamous epithelium (2).

(59) Organ: Esophagus-dog. Esophagus dog Stain : H&E. Lesion: Oseous metaplasia. p

Micro: Focal replacement p of the fibrotic tissue ((l)) with bone spicules(2).

(60) Organ: Liver (bile-duct) Stain : H & E. Lesion:

Hyperplasia of the epithelial lining of ducts ducts. Micro: The epithelial-lining of the bileducts proliferated and formed branched finger-like processes with connective tissue i core which hi h projected j d iinside id the h lumen of bile-duct (l). Numerous oocysts of coccidia(2) (Emieria stiedae), stiedae) are seen inside the lumina of the bile ducts.

(61) Tissue of origin: Squamous epithelium. epithelium Stain : H & E. Lesion:

Squamous cell papilloma Micro.: Hyperkeratosis (l) and acanthosis (2) with i h iintact b basall cellll llayer(3). (3) The epidermis is evaginated taking with it a fibrous tissue core. core

(62) Tissue of origin: Squamous epithelium. epithelium Stain: H&E. Lesion:

Squamous cell carcinoma.

Micro: Irregularly rounded prickle-cells (singly or in groups) are infiltrating deeply in the tissue in the form of branched cords. Cross-secion of such a cord takes the shape of cell nest (l) or epithelial pearl (from periphery to center, large a ge polyhedral po y ed a cells ce s are a e followed o owed with w t crescentic c esce t c cells ce s surrounding s o d ga keratinized center). The intercellular bridges are seen. The stroma (2) is distinct.

(63) Tissue of origin: Epithelial cells. cells Stain: H&E. Lesion:

Basal cell carcinoma.

Micro: The neoplasm appears in the deep layer of the dermis in the form of irregularly rounded nodules(l) embedded in a distinct stroma( stroma(^2) 2) and surrounded by a connective tissue capsule(3). The neoplastic cells, inside each nodule, are small, oval, hyperchromatic and arranged in entangled rows with i h the h llongitudinal i di l axis i off the h cells ll perpendicular di l on the h longitudinal axis of the rows.

(64) Tissue of origin: Gl d l epitheliumGlandular i h li perianal gland. Stain: H&E. Lesion:

Adenoma. Micro: The usual histological picture of the gland is seen in the form of lobules(l) with interlobular connective tissue and blood-vessels(2). Each g y rounded cells which lobule consists of irregulary are small on the periphery (reserve cells) and large towards the center.

(65) Tissue of origin: Glandular epithlium (uterus). Stain : H & E. Lesion:

Papillary adenoma.

Micro: Th neoplastic The l ti cell, ll lining li i the th endometrium, d ti formed f d branched projections (l) with fibrous tissue stroma(2) inside the uterine lumen. The uterine glands(3) are numerous. The basement membrane is intact.

(66) Tissue of origin: Glandular epithelium. Stain : H&E. Lesion:

Adenocarcinoma .

Micro: The acini are lined by more than one layer of epithelium p which form entangled g branches inside the lumina. The glandular tissue is frequently replaced by masses of undifferentiated epithelium. The basement membrane is broken or absent. absent Necrosis is extensive. extensive

(67) Tissue of origin: Glandular epithelium. Stain :H&E. Lesion:

Metastatic adenocarcinoma. d oc c o .

Micro.: Cuboidal or low columnar epitheli m (1) is arranged in the form of epithelium rows or tend to form acini, which partially replaced the affected pulmonary tissue. The nuclei are hyperchromatic and the stroma is distinct The air vesicles, around the lesion, are collapsed.

(68) Tissue of origin: Epithelial tissue tissue. Stain :H&E. Lesion:

Carcinoma simplix. simplix

Micro.: The neoplasm p is represented p byy numerous large g cells with large rounded, vesicular and hyperchromatic nuclei, showing numerous typical and atypical mitotic figures figures. The nucleoli are large and the stroma is indistinct.

(69) Tissue of origin: Fibrous connective tissue. Stain :H&E. Lesion: i

Fibroma. Micro.: The neoplasm consists of bundles of fibroblasts andd collagen ll fib fibers, running i iin various i directions. The fibroblast is represented by a p nucleus, with tapered p ends and spindle condensed chromatin. The neoplastic fibrous tissue usually forms whorls.

(70) Tissue of origin: g Fibrous tissue and

squamous epithelium. epitheli m Stain: H&E. Lesion:

Fibropapilloma . Micro : Both squamous cell papilloma and fibroma are seen.

(71) Tissue of origin: Fibrous connective ti tissue ti andd glandular l d l epithelium Stain : H&E. Lesion:


Micro : Both adenoma and fibroma are present. The adenoma is represented by the proliferated diff differentiated i d glandular l d l tissue i with i h iintact basement membrane. p by p proliferated The fibroma is represented fibroblasts and collagen fibers running in various directions and forming whorls.

(72) Tissue of origin: White fibrous connective tissue. Stain: H&E. Lesion: i

Myxoma. Micro: The neoplasm is represented by stellate, rounded and oval cells with dark nuclei which follow the shape of the cell. These cells are widely separated from each other by bluish structurless mucoid substance which contains blood-vessels, lymphatics and cellular processes criss-crossing each other.

(73) Tissue of origin: Adipose tissue. tissue Stain: H&E. Lesion:


Micro: Neoplastic cells are similar to the normal adipocytes di ((wellll differentiated) diff i d) except they h are irregularly rounded and of variable sizes A few collagen fibers are seen among sizes. them.

(74) Tissue of origin: Hyaline cartilage. Stain: H&E. Lesion: Chondroma. Micro: The lacunae, in normal cartilage, contain 24 chondrocytes of almost the same size. In chondroma, usually one chondrocyte is seen inside each lacuna. These chondrocytes are of variable sizes and shapes. p Blood vessels are p present in the connective tissue capsule which divides the tumor into lobules.

(75) Tissue of origin: Hyaline cartilage. Stain: H&E. Lesion: Chrondrosarcoma

Micro: The neoplasm is highly cellular due to the small oval or spindle and hyperchromatic nuclei of the neoplastic chondrocyes which destroyed their lacunas, proliferated and infiltrated the surrounding tissue. Mitotic figures are numerous. p blood-vessels in the form of spaces p surrounded with the neoplastic p cells are II-developed seen in addition to necrosis and hemorrhage. The presence of remnants of normal carilage helps the diagnosis.

(76) Tissue of origin: Bone. Stain :H&E Lesion: Osteosarcoma

Micro :Similar to chondrosarcoma, except for the presence of remnants of bone which help the differential diagnosis.

(77) Tissue of origin: Periosteum Stain :H&E. Lesion: Metastatic osteosarcoma (osteogenic sarcoma).

Micro.: Similar to osteosarcoma, except it is well circumscribed well-circumscribed. The surrounding air vesicles are collapsed.

(78) Tissue of origin: Osteoclasts. Osteoclasts Stain :H&E. Lesion:


Micro.: The neoplasm is represented by numerous multinucleated osteoclasts(1), mixed wit neoplastic spindle cells

(79) Tissue of origin: Fibrous connective tissue. Stain: H&E. Lesion: i

Equine q sarcoid.

Micro: The neoplasm is mixture of fibroma, fibrosarcoma snd extensive inflammation with necrosis. The fibrosarcoma is represented by bundles of oval, vesicular si l r and nd hyperchromatic h p r hr m ti llarge r n nuclei l i with ith numerous mitotic figures. These bundles are running in various directions. The stroma is indistinct.

(80) Tissue of origin: Endothelial lining of blood-vessels. Stain: H&E. Lesion: i

Capillary or plexiform hemangioma. Mi r : Micro The neoplastic endothelium formed differentiated p capillaries.

(81) Tissue of origin: Endothlial lining of hepatic sinusoids. Stain: H&E. Lesion: i

Cavernous hemangioma. Micro: The neoplastic endothelial lining of the hepatic sinusoids formed cavities of irregular sizes and shapes lined with endothelium and filled with blood which replaced the hepatic cells in the affected area.

(82) Tissue of origin: Lymphoid tissue (spleen). S i H&E. Stain: Lesion:

Benign B i lymphoma. Micro: Focal proliferation of the neoplastic lymphocytes which replaced the white and red pulps. Some lymphocytes are aggregated in the form of follicles. follicles The neoplastic cells are similar to the small lymphocytes.

(83) Tissue of origin: Lymphoid tissue. Stain: H&E. Lesion: y p Lymphosarcoma (small-cell type).

Micro: All the structures of the lymphoid tissue are repaced by small rounded lymphocytes (10 microns diameter). diameter) Their large nuclei occupied all the cytoplasm with peripherally condensed chromatin and surrounded by a thin layer of cytoplasm.

(84) Tissue of origin: Lymphoid tissue. tissue Stain: H&E. Lesion: Malignant y p lymphoma (histiocytic type).

Micro: The structure of the affected tissue is replaced by large lymphocytes with large vesicular and hyperchromatic nuclei and abundant eosinophilic cytoplasm.

(85) Tissue of origin: Lymphoid tissue. tissue Stain : H & E. Lesion: Malignant y p ((stemlymphoma cell type).

Micro: The structure of the affected tissue is replaced by large lymphocytes with large i irregular l nuclei l i andd scanty cytoplasm. l

(86) Tissue of origin: S Smooth th muscle l Stain: H&E. Lesion:


Micro: Bundles of smooth muscle fibers (represented by elongated nuclei with round ends and granular chromatin) are running in various directions. directions

(87) Tissue of origin: Undecided. Undecided Stain: H&E. Lesion: Canine transmissible venereal tumor.

Micro: The tumor consists of large polyhedral cells of almost the same size and adjacent to each other. Their nuclei are large, round, vesicular, hyperchromatic and g Fine fiber strands are seen amongg show mitotic figures. the cells as if they separate them into columns.

(88) Tissue of origin: Melanoblasts. Melanoblasts Stain : H& E. Lesion:

Malignant melanoma Micro: The tumor consists of spindle, spindle oval or irregularly rounded melanoblasts with numerous brownish p pigments g inside the cytoplasm. The pigments may overshadow the structure of the cell.

(89) Tissue of origin: Melanoblass Stain : H&E. Lesion:

Amelanotic melanoma. l Micro: The tumor is highly cellular and consists of irregularly rounded large cells with enlarged vesicular nucleus which is hyperchromatic and sh s mitotic shows mit ti activity. ti it Almost no melanin is seen in the cytoplasm of the neoplastic melanoblasts.

(90) Tissue of origin: Metanephros. Stain : H&E. H&E Lesion: Nephroblastoma. Micro: Aggregations of epithelial cells which tend to form glomerular like structures (l) (without capillaries), solid masses of epithelium or tubular like structures are scattered in a connective tissue stroma(2).

(91) Tissue of origin: Nerve sheath cells. Stain: H&E. Lesion: Neurofiberoma. Micro: Palisading of fusiform nuclei which frequently formed whorls, waves and pacinian corpuscle-like p p structures.

(92) Tissue of origin: Mesothelium (pleura). Stain: H&E. Lesion: i


Micro: Extensive replacement of the pulmonary tissue with arboreal structure forming numerous branches covered with columnar mesothelium, surrounding connective i tissue i core which hi h was ffrequently l ossified.

General Pathology