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DISEASES OF THE BLOOD VESSELS: DEGENERATIVE,
INFLAMMATORY AND CONGENITAL DISORDERS
STRUCTURE AND FUNCTION OF THE BLOOD SYSTEM
there are four major parts of blood circulation
-systemic
-pulmonary
-portal
-lymphatic
SYSTEMIC CIRCULATION
-supplies arterial blood to the tissues
- it begins at the aortic valve and ends at the endings of large veins
(v.cava sup. and vena cava inf.) where they enter right heart atrium
systemic circulation is composed of:
1- elastic arteries- including the aorta and its major branches
-the main function is to convert and transmit discontinuous cardiac
output to continuous blood flow in arteries
2- muscular arteries- coronary, carotid, branchial, femoral, renal,
mesenteric
-the main function is to distribute the blood to the tissues
3- arterioles- arteries less than 2 mm in diameter, they have
muscular wall
- the main function is to regulate the blood pressure decrease from
aortic to capillary levels
4- microcirculation- consists of precapillary sphincters, capillaries
and postcapillary venules
-the main function is- to be the site of exchange of oxygen and nutrition
for the tissues
5- veins - are low pressure vessels (with help of endothelial valves)
-the main function: to return the blood to the heart
PULMONARY CIRCULATION
- is a low pressure system
- it begins at the pulmonary valve and ends in the left atrial opening
- the main function is to effect respiratory gas exchange in the
pulmonary capillary circulation
PORTAL CIRCULATION
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- is a special portion of systemic circulation to serve a specific functionportal circulation delivers intestinal and splenic blood with substances
absorbed from the intestine to the liver
LYMPHATIC CIRCULATION
- lymphatic vessels originate within the interstitial tissue and end in the
opening of the thoracic duct into the jugular vein
- main function: transport large molecules and excess fluid back to the
blood from the interstitial tissue
-the lymphatic system operates at a very low pressure - valves
lymph nodes- interspersed in the lymphatic flow
Clinical manifestations of blood vessel diseases.
-pathologic changes in blood vessels have one or more basic
consequencies
 narrowing of the lumen with parenchymal ischemia and potential
infarction in the tissues supplied by the involved blood vessel
 damage to the intima with thrombosis
 weakening of the wall with dilatation (aneurysm) and/or potential
rupture of the blood vessel

Congenital anomalies of blood vessels.
1- berry aneurysm- caused by congenital focal weakness of the
blood vessel wall results in outpouching of the artery-often at the site of
branching
-they occur in cerebral vessels, arteries of the circle of Willisweakening of the wall can lead to fatal rupture of the involved arteryresulting in subarachnoidal hemorrhage
2- arterio-venous fistula- is an abnormal communication between
the vein and the adjacent artery
-may be congenital or caused by trauma, or arterficial
-large fistulas may cause left-to right shunt with an increase of venous
return - possible right heart failure
ACQUIRED DEGENERATIVE DISEASES OF BLOOD VESSELS.
ARTERIOSCLEROSIS
-is a slowly progressive disease of arteries, characterized by
thickening and loss of elasticity of arterial walls
- more than half of all deaths in the States are attributable to
complication of atherosclerosis, among which particularly important are
ischemic heart disease, myocardial infarction , and cerebrovascular
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disease, aneurysm rupture, mesenteric occlusion with bowel necrosis, and
gangrene of lower extremities
-three major patterns
of arteriosclerotic changes can be
distinguished:
 a) atherosclerosis
- is a slowly progressive d. of arteries characterized by elevated intimal
fibrofatty plaques, formed by lipid deposition, smooth muscle
proliferation and synthesis of extracellular matrix
- any artery can be involved, mostly large to medium-sized muscular
arteries and large elastic arteries are involved, particularly the aorta,
and its branches, but also coronary arteries, and arteries of the circle of
Willis, etc.
 b) Monckeberg's medial calcific sclerosis
-characterized by calcifications of the media of muscular medium-sized
arteries, intima is usually not involved
-femoral, tibial, radial an ulnar arteries are affected
-pathogenesis is unknown, process is unrelated to atherosclerosis
 c) arteriolosclerosis
-affects small arteries and arterioles
-occurs in two variants, as hyaline and hyperplastic, both cause thickening
of the vessel wall with luminal narrowing
 hyaline arteriolosclerosis- is characterized by diffuse pink hyaline
thickening of the arteriolar wall
-occurs typically in older pateints
- often affects the kidney- causes benign nephrosclerosis grossly:
- the kidneys are symmetrically atrophic, finely granular surface
microscopically:
- hyaline thickening of the walls of the small arteries and arterioles
(homogenous, pink) with narrowing of the lumena
- decrease of the blood flow through affected vessels- causes ischemia
and ischemic atrophy of the kidney
- in younger patients- associated with arterial hypertension and DMfrequency and severity of the lesions is increased
 hyperplastic arteriolosclerosis – less common, characteristic of
malignant hypertension - microscopically- concentric lamellar „onionskin“ arteriolar thickening with reduplication of basement membrane
and smooth muscle cell proliferation- fibrin deposition and vessel wall
necrosis
 ATHEROSCLEROSIS
- is the most important pattern in arteriosclerosis
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 pathogenesis and epidemiology:
multifactorial, idiopathic, not completely understood
risk of development of atherosclerosis increases with
-age,
cigarette
smoking,
positive
family
history,
hypertension, diabetes mellitus, and hypercholesterolemia
-major acquired risk factors:
1) acquired hyperlipemia
2) hypertension
3) cigarette smoking
4) diabetes mellitus
-the risk is correlated with elevated serum levels of low-density
lipoprotein (LDL)
-the higher total cholesterol level, the greater risk of AS
-genetic and acquired diseases that lead to early hypercholesterolemia
usually cause premature AS in young persons (congenital familiar
hypercholesterolemia, DM, hyperthyroidism)
-inverse relationship between symptomatic AS and high-density
lipoprotein- HDL because HDL helps to clear cholesterol from vessel wall
lesions.
-less prominent influences on the risk of atherosclerosis include
obesity, sedentary or high-stress life style, and type A personality
pathogenesis:
- most theories invoke some damage to endothelium or underlying smooth
muscle with subsequent proliferation of smooth muscle cells
"response-to-injury-hypothesis"
- according to this idea- atherosclerosis is a reaction to chronic repeated
endothelial cell injury, caused by such insults as hyperlipidemia,
hypertension, products of cigarette smoking, diabetic microangiopathy,
circulating endotoxins, anoxia, hypoxic changes, viruses, turbulent blood
flow,etc.
-endothelial injuries induce metabolic and structural changes
accompanied by increased permeability to plasma constituents, such as
lipids, lipoproteins, mainly cholesterol - these substances may accumulate
within the intima at these sites of endothelial injury- because of local
increase of endothelial cell permeability
-subsequent cellular events include imigration of macrophages into
the intima- these change to foamy cells
-endothelial injury also result in adhesion of platelets and
monocytes and release of factors from activated platelets and
monocytes, such as PDGF- platelet-derived growth factor, induce smooth
muscle proliferation and their migration to the intima,
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-smooth muscle cell produce large amounts of extracelular matrix
components, such as collagen, elastic fibres, proteoglycans
-smooth muscle cells accumulate lipid (cholosterol) to become foam
cells
 MORPHOLOGY OF ATHEROSCLEROTIC LESIONS
there are two main types of lesions in AS
-fatty streaks and atheromatous plaques
 1) FATTY STREAKS
-are thin flat yellow streaks in the intima- caused by lipid
depositions in the cytoplasm of intimal mesenchymal cells and in
macrophages- aggregates of foamy cells
-they may occur in the aorta very early in life- are harmless and
reversible in early stage- there is not a obvious relation to AS- some of
them disappear, some may progress to atheromatous plaques- many
believe however that fatty streaks are precursors of AS plaques
 2) ATHEROMATOUS PLAQUES- fibrofatty atheroma - fibrous
plaques
-early changes- monocytes adhere to endothelial cells close to the site of injurymigrate between endothelial cells to get to the subendothelial spacethan change to foamy cells
- in addition- smooth muscle cells from the media layer- become larger
and proliferate- these cells also take up lipids to form foam cellsaggregates of foam cells within the intima = fatty streaks
- then smooth muscle cells proliferate around foci of foam cells
-smooth muscle cells can synthesize collagen, elastin, proteoglycoproteins
- this proliferation of SMCs is governed and controlled by growth
factors, such as
-PDGF (platelet-derived growth factor)-released by platelets,
macrophages, endothelial cells and SMCs
-epidermal growth factor (EGF)
-transforming growth factor (TGF-alfa)
-later stage- MATURE FIBROFATTY ATHEROMAS (intimal plaque)
-is composed of aggregates of foam cells and macrophages and SMCs,
extracellular lipids, cellular debris, fibroblasts and collagenous matrix
-with proggresion of the disease- fibrofatty atheroma is modified by
further deposition of collagen, elastin, proteoglycans. Atheromas undergo
considerable cellular proliferation and formation of fibrous connective
tissue = FIBROUS PLAQUES
-SECONDARY CHANGES IN ATHEROMATOUS PLAQUE-dystrophic calcification-very common
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-severely affected vessels- can be changed into completely calcified rigid
tubes
-ulceration of the overlying endothelium - thrombosis of the
plaque- most common complication
-thrombosis- often associated with ulceration -parts of atherothrombotic masses- may be discharged to the blood stream as emboli
-vascularisation of the plaques- may lead to the hemorrhage in the
plaques- occlude the lumen (coronary vessels)
-aneurysms may develop in vessels weakened by extensive plaque
formation- the abdominal aorta is a favorite site
HYPERTENSIVE VASCULAR DISEASE AND ARTERIOLOSCLEROSIS.
-hypertension is the single most important risk factor in both coronary
heart disease and cerebrovascular accidents
-it may also lead directly to congestive heart failure (hypertensive heart
disease), to renal failure and aortic dissection
-90% of hypertension is primary and idiopathic- essential
hypertension-10% of hypertension is secondary-mostly related to renal disease,
endocrine abnormalities, vascular malformation
blood pressure- is a complex trait that is determined by the interaction
of multiple genetic and environmental factors that regulate the
relatioship between cardiac output and total arteriolar resistence
-vasoconstriction- increases vascular resistence- vasoconstrictive
factors include angiotensin, catecholamines, etc
-vasodilatation- is regulated by kinins, prostaglandins, etc
-cardiac output is regulated by blood volume- depends on sodium
level, natriuretic factors, heart rate, etc.
pathogenetic mechanisms leading to essential hypertension-essential hypertension is either related to a primary increase in
cardiac output (retention of natrium)
-or to an increase in peripheral resistence- release of
vasoconstrictive factors, neurogenic causes, increased sensitivity of
smooth muscle cells, etc.
Morphologic changes in hypertension:
-hypertension accelerates development of atherosclerosis
-hypertension is associated with small vessel disease, called
arteriolosclerosis- two types- hyaline and hyperplastic- both
characterized by diffuse arteriolar wall thickening
INFLAMMATORY DISEASES OF BLOOD VESSELS.
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1) POLYARTERIITIS NODOSA
=systemic disease characterized by necrotizing inflammation of mediumand small-sized arteries throughout the body sparing the pulmonary
circulation
-most often - in middle aged adults, more often in males
 morphology of PAN:
- the disease is characterized by fibrinoid necrosis of the intima,
and heavy mixed inflammatory infiltration in and about the vesselinfiltrates composed of lymphocytes, plasma cells and leukocytes
-vasculitis in acute phase is characterized by transmural inflammation
composed of neutrophils, eosinophils frequently associated with fibrinoid
necrosis of the inner half of the vessel wall
- the lumen becomes thrombosed- results in acute tissue ischemia and
infarction
- in later stage- nodular fibroblast proliferation and irregular aneurysmal
dilatation of blood vessels
 Cause and pathogenesis:
-pathogenesis is still not completely understood -either the
vascular lesions are caused by immune complex mediated reaction-possible mechanism has been proposed recently- ANCA ( antineutrophil cytoplasmic antibodies) have been identified in the circulation
of 75 % of patients
-ANCA interact with activated neutrophils and monocytes-which results
in a release of toxic oxygen radicals- damage of endothelial surfacevasculitis
 Clinical course:
virtually all organs may be affected with exception of the lungs,
most commonly affected- are kidney, heart, liver, GIT
- unpredictability of the organ involvement leads to a variety of
clinical symptoms including malaise= vague feeling of physical discomfort,
fever, weakness, weight loss
-renal involvement- possible cause of death
- vascular lesions of the GIT- abdominal pains, diarrhea, melena
- peripheral neuropathy
2) WEGENER'S GRANULOMATOSIS
= is characterized by complex of three major symptoms 1) necrotizing
granulomas of the upper respiratory tract and 2) necrotizing or
granulomatous vasculitis of small arteries and veins most commonly in the
lungs and 3) necrotizing glomerulonephritis
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pathogenesis: no etiological agent has been identified
-immune complexes are occasionally present in vessell walls and glomeruli,
most patients have entineutrophilic cytoplasmic autoantibodies ANCA
morphologically:
-inflammatory sinusitis due to granulomas in the mucosa of the upper
respiratory tract
-or large ulcerative lesions of the nose, palate, pharynx
-in the lungs- focal necrotizing granulomas (grossly visible nodules) with
central necrosis surrounded by the rim of lymphocytes, plasma cells and
macrophages, including the giant cells
-necrotizing or granulomatous vasculitis of small arteries and veins
-scattered eosinophilic leukocytes
-more severe lesions and inflammatory involvement of capilaries- alveolar
hemorrhages
clinical symptoms:
-males affected more often
-symptoms similar to those of PAN
the course of untreated disease - is progressive
diagnosis: - biopsy of upper respiratory tract lesions
appropriate therapy: prednisone+ antibiotics
3 ) TEMPORAL ARTERITIS ( GIANT CELL ARTERITIS)
=characterized by segmental acute granulomatous vasculitis
-involves mostly large arteries of the head and neck region (branches of
the carotid artery), other arteries may be affected, including the aorta,
arteries of the brain
never affected- arteries of the lungs and heart
-more often in females, adult age (mostly after age of 50)
-most patients have systemic signs, including fever, weight loss, fatique
-local signs of pain called polymyalgia rheumatica (pain and stiffness of
the muscle of hip and shoulder girdles) and headache
morphologically:
-short segments of involved arteries are thickened -with reduction of
the lumen- slit-like lumen may be thrombosed
histologically: two possible patterns1)granulomatous inflammatory reaction of the inner half of the media
consisting of macrophages, multinucleate giant cells of Langhans type and
lymphocytes
2) in other cases- rare granulomas, but instead of this - nonspecific
diffuse inflammatory infiltrate composed of lymphocytes, leukocytes adn
macorphages
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later stage: collagenous thickening of the vessel walls
4 ) TAKAYASU ARTERITIS ( SO CALLED PULSELESS DISEASE)
=is a chronic vasculitis- principally involves the aorta and its main
branches and sometimes pulmonary arteries
-predominantly in persons younger than 40, strong female preponderance
morphology:
-thickening of the aortic wall and narrowing of the orifices of the great
aortic branches
-origins of coronary and renal arteries may be involved- may lead to IM
histologic changes:
-in earlier active stage- prominent granulomatous arteritis- inflammation
mostly affects the media and adventitia- at this stage- the histologic
findings are reminiscent to those in temporal arteritis
- prominent lymphocytes and plasma cells, numerous giant cells of
Langhans type
-in later stage: only collagenous thickening persists
pathogenesis: immune mechanisms suspected, but not well established
clinical symptoms:
-vascular insufficiency of the extremities (mainly the upper ones)coldness of the fingers
-if lower portion of the aorta is affected- claudications in the legs (pain
of muscles after exercise)
5 ) KAWASAKI DISEASE ( mucocutaneous lymph node syndrome)
=a self-limited acute disease of infancy and childhood characterized by
fever, enlargment of cervical lymph nodes and acute vasculitis
- commonly- coronary arteries are involved - lead to arythmias,
cardiac dilatation, congestive heart diseas or even acute infarction
pathogenesis:- unknown
- vasculitis is caused by autoimmune reaction due to formation of
antibodies to endothelial cells- acute vasculitis- lead to aneurysm
formation or superimposed thrombosis
morphology: in acute phase- vasculitis and perivasculitis of small vessels
with main involvement of the intima
6 ) THROMBANGIITIS OBLITERANS ( BUERGER'S DISEASE)
=is a chronic relapsing inflammatory vascular disease characterized by
acute and chronic vasculitis of medium-sized and small arteries followed
by thrombosis of affected vessels and severe vascular insufficiency
-mostly affected- arteries of lower extremities- may lead to gangrene
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pathogenesis: unknown, but closely related to the use of tobacco products
-tobacco smoking (clear mechanism is not established yet) leads to
endothelial damage- either direct toxicity or it initiates immune reaction
morphology:
-arterial walls are infiltrated by mixed inflammatory cells, mostly
lymphocytes, the lumen is closed by thrombosis
-thrombus typically contains small microabscesses- inflammatory reaction
may extend to acompanying veins and nerves (organization of thrombi)
clinical symptoms: claudications, color and temperature changes in lower
extremities
-chronic ulcerations of the toes, feet, fingers- gangrene, severe pain
even at rest
-stop of cigarette smoking-relief from further attacks
7 ) RAYNAUD'S DISEASE
=paroxysmal pallor or cyanosis of acral parts (fingers, tip of nose, ears)
caused by intense spasm of small arteries and arterioles
-idiopathic disease in young women
-in contrast, Raynaud syndrome refers to arterial insufficiency of acral
parts caused by some other disorders, such as atherosclerosis, Buerger
disease, vascular disease in lupus erythematodes
in later stage- trophic changes, ulcerations in the skin, areas of gangrene
in finger tips
8) LEUKOCLASTIC ANGIITIS
-disease involves small vessels than PAN, lesions are characterized
by fibrinoid necrosis and rich lekocytic infiltration within the affected
blood vessel wall
-pathogenesis: imune complexes in previously sensitized person,
intiated by drugs, microorganisms, heterologous protein, etc
ANEURYSMS
= abnormal focal dilatation of arteries or veins
-develop wherever there is marked weakening of the wall of the vessel
most common causes of aortic aneurysms
-atherosclerosis
-syphilis
-cystic medionecrosis
causes of other aneurysms:
-congenital (intracranial arteries)- may lead to cerebrovascular
accidents
-traumatic
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-mycotic- due to local inflammation
1) atheroclerotic aneurysms- is by far the most common
-mostly affected- abdominal aorta
morphology:
-AS aneurysms take form of saccular or cyllindroid swelling
-mural thrombus is frequently found within the aneurysmal sac
-thrombus may even completely fill the sac of the aneurysm
clinically:
-parts of thrombus from the aneurysm may embolize
-occlusion of renal, mesenteric or other arteries may result from the
pressure in the aneurysmal sac
-most important- rupture- rare in smaller, very often in larger than 6
and more cm in diameter
2) syphilitic aortitis and aneurysm-syphilitic aortitis- mostly restricted to thoracic aorta
histologic findings:
-in early stage- obliterative vasculitis affects vasa vasorum of the aortainflammatory reaction within the aortic wall is composed of lymphocytes
and plasma cells
-in the media- ischemic necrosis and scarring- the aorta loses the
elasticity- tends to be dilated- followed by formation of the aneurysm
-syphilitic aneurysm may be superimposed by atherosclerosis- often filled
with thrombus
-may cause erosin of bone- pressure atrophy- may cause respiratory
insufficiency or problems with swallowing
-pain, cardiac disease, death of heart failure or rupture of the aorta
3) dissecting aneurysm (= dissecting hematoma)
= special type of aneurysm, characterized by the intima defects that
allows the blood to penetrate into the aortic wall with propagation of
hemorhage along the vessel
clinically:
- severe chest pain (dif.dg.includes IM)- first symptom in most cases
- abdominal pain due to compresion of mesenteri arteries
- sudden decrease of blood pressure
treatment:
- immediate administration of antihypertensive drugs
-replacement of the affected part of the aorta by the graft
morphology:
-longitudinal tears in the intima of the aorta (sharp, irregular edges)
-blood enters through the intimal defect into the media- hematoma
-typically devides the outer and middle thirds of the aorta
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-the hemorhage may dissect in proximal direction to the heart or to the
periphery
-histologically
-in most cases- very few abnormal findings
-in about 20%- focal areas of degenerative changes in the media known
as cystic medionecrosis Erdheim (may be a part of Marfan syndrome)
VENOUS DISEASES
two most important diseases- varicose veins and phlebothrombosis
1) VARICOSE VEINS - abnormally dilated tortuous veins
-varicose change is caused by higher pressure in the venous lumen
-most commonly affected- superficial veins of the leg
causes:
-degenerative changes in vessel walls, muscle atrophy,
-higher
intraluminal pressure
-familial tendency
-any impediment of blood circulation, such as slow down of the blood
movement, type of dressing, etc.
morphology:
-affected veins are dilated, tortuous and elongated
-dilatations are irregular
-focal thickening of the blood vessel wall
-common complication- is intraluminal thrombosis =phlebothrombosis
special types of venous varicosities:
1) hemorrhoids- result from varicose dilatation of the hemorhoidal
plexus of the vein at the anorectal junction- bleeding to GI- melena
2) varicose veins in the esophagus- in patients with portal
hypertension- due to liver cirhosis- rupture may cause death
clinically:
-lower extremities varicose veins- usually asymptomatic, rarely pain, but
often followed by thrombosis of the venous plexuses
 THROMBOEMBOLIC DISEASE
-thrombi most common- in deep veins of the lower extremities- source
of pulmonary embolism
 OBSTRUCTION OF VENA CAVA SUPERIOR
-usually caused by tumors that compress the lumen of the VCS- most
commonly in bronchogenic carcinoma or mediastinal malignant lymphoma
-distinctive clinical complex, referred to as superior vena cava syndrome
- includes cyanosis, marked dilatation of the veins of the head and neck
region, severe edema
 OBSTRUCTION OF VENA CAVA INFERIOR
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-may be caused by tumors that either compress or penetrate the wall most common in renal cell carcinoma and hepatocellular carcinoma
-or by upward propagation of the thrombus from the femoral vein with
occlusive thrombosis
-marked edema
TUMORS OF BLOOD AND LYMPHATIC VESSELS
benign-benign vascular tumors are very common-most frequently
are seen in skin
-benign tumors with endothelial cell differentiation - produce
readily recognizable vascular channels with apparent erythrocytes within
the lumina
- the channels are lined by neoplastic endothelial cells
-these cells express factor-VIII related antigen, CD34 and other
markers similar to normal endothelial cells
-they have electron microscopical features similar with normal
endothelium, such as presence of Weibel-Palade bodies

1) CAPILLARY HEMANGIOMA
-most common sites - skin, subcutaneous tissue, mucous membranes of
oral cavity and lips,
less common sites- spleen, liver, salivary glands, etc.
-grossly: bright red or bluish lesions of various size, may level with the
surface or may be elevated
-usually present at birth, may regress spontaneously
-morphology:- composed of capillary-like channels lined by endothelial
cells and filled by blood or lymph,
-these channels are separated one from another by a scant connective
tissue stroma
-thrombosis or fibrous organisation in the lumina- common
2) CAVERNOUS HEMANGIOMA
-occurance - skin, subcutaneous tissue, internal organs, such as spleen,
liver, pancreas
- multiple vascular tumors in cerebellum, brain stem and internal organsassociate in clinical syndrome called HIPPEL-LINDAU DISEASE
grossly: red- blue spongy large lesions, with sharply defined margins,
histologically- composed of partly thrombosed channels lined by
neoplastic endothelium
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3) EPITHELIOID HEMANGIOMA
-is a benign vascular tumor with well formed but often immature vessels,
the majority of which are lined by plump (epithelioid) endothelial cells
-most cases have a prominent inflammatory component
sites of involvement: -predilection to head and neck region, especially
forehead
morphology:
-multiple small nodular lesions in subcutaneous connective tissue
-affects wide age range with peak in 3rd to 5th decades, more common in
males
histologically- the lesion is composed of abundant well-developed
capillaries lined by epithelioid endothelium surrounded by heavy
inflammatory infiltrate, mostly of eosinophilic leukocytes
clinical course- majority of patients present with a mass of one year and
less in duration, the process is usually uninodular, but sometimes
multinodularity is encountered, complete local excision is optimal
treatment- local recurrences have been reported, but no metastases
were identified
 intermediate vascular neoplasms (borderline)
1) EPITHELIOID HEMANGIOENDOTHELIOMA
-is an angiocentric vascular tumor with metastatic potential, composed of
epithelioid endothelial cells arranged in short cords and nests in
myxohyaline stroma
Sites of involvement: the tumor develops in deep soft tissue of
extremities, less commonly in bone, liver and lungs
Clinical features: the tumor develops painful nodule-behaviour is
intermediate with an uncertain clinical course-it is locally aggressive,
recurrence rate is 10-15%, metastatic rate about 25%
morphology- depends on location of the tumor:
-in soft tissues- the tumor is composed of solid nests and short cords of
spindle or epithelioid cells with only rare abortive vascular channels
- in some cases, a vascular differentiation is more primitive, and is
expressed at the cellular level only- as small intracellular lumina that
occasionally contain erythrocytes
-in lungs- the same tumor has been previously described as intravascular
bronchioloalveolar tumor- IVBAT because of its resemblance to epithelial
tumor
 morphology: one or multiple bilateral nodules in pulmonary parenchymacomposed of hypocellular sclerotic center bordered by more cellular
periphery that is formed by epithelioid endothelial cells
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- tumor increases in size, may invade a pleura or may posses an
endolymphatic spread
-in liver- tumor is characterized by nodular growth pattern and may be
confused with sclerosing epithelial tumor, such as cholangiocarcinomapoor prognosis, more than 50% metastasize
 malignant
1) ANGIOSARCOMA- is a rare malignant tumor the cells of which
recapitulate the features of endothelium
Sites of involvement: most lesions develop as cutaneous tumors in old
patients, affect the skin of head and neck region, less commonly soft
tissues are affected
morphology: composed of malignant polymorphic cells with endothelial
differentiation of various degree
clinically- are highly aggressive tumours- local recurrences develop in
30%, one half of patients are expected to die of tumour within one year
after diagnosis with metastases in the lungs, bone, lymph nodes, soft
tissues, etc.
2) KAPOSI SARCOMA
KS is a locally aggressive endothelial tumour that typically presents with
cutaneous lesions in the form of plaques, nodules, pathes but may also
involve mucosal sites, lymph nodes and visceral organs,
earlier- it was a rare tumor, nowadays more common- in immunosupressed
patients and particularly important- in AIDS
the tumor is uniformly associated with human herpes virus 8 (HHV-8)
infection
Four major clinical and epidemiological forms of KS are recognized:
 a) classic variant of KS (European KS)
-a relatively indolent disease that typically affects elderly persons,
more commonly males,
-the lesion consists of multiple red to purple cutaneous plaques and
nodules on the lower extremities
-histologically- the lesions are composed of irregular angulated blood
vessels lined by endothelial cells- interspersed infiltrate composed of
lymphocytes, plasma cells and macrophages
- over time- the lesions tend to become more numerous, and vascular
channels are
lined by swolled plumped endothelium, scattered extravasated RBCs, deposits of hemosiderin, hemorhages
-typical finding- pink hyaline globules in spindled cells and macrophages
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-this form rarely causes death, disease is restricted to the surface of
the body
 b) KS associated with AIDS
-may begin as multiple large nodules in the skin, later other sites are
affected, such as mucosal membranes, lymph nodes and visceral organs
microscopically:
-lesions are composed of scattered small vascular channels and
slit-like spaces with RBCs within the lumina, marked hemorrhage,
hemosiderin pigment, lymphocytes, macrophages
very common- pink hyaline globules, brisk mitotic activity
-clinically this AIDS related form of KS- is much more aggressiveusually fatal within 2-5 years-there is no useful therapy, the disease
tends to spread rapidly, with common visceral involvement
 c)African KS- is clinically similar to the classic form, but occurs in
younger men in central Africa
 d)Transplant-associated
KSoccurs
in
patients
undergoing
immunosupressive therapy, there is both cutaneous and visceral
involvement, the lesions may regress when immunosupression is
discontinued