Med 4 Pigmented Lesions of the Skin

7/31/2019 Med 4 Pigmented Lesions of the Skin

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e c nee c ne

Pigmented Lesions of the Skin.Pigmented Lesions of the Skin.


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HSk13aHSk13a This draw ing show s t he main cells t hat const it ute the epiderm is.This draw ing show s t he main cells t hat const it ut e the epiderm is.Kerat inocytes originat e fr om t he mit osis of basal cells and migrat e progressivelyKerat inocytes originat e fr om t he mit osis of basal cells and migrat e progressivelyu w ards unt il t he become kerat inized and are shed. Lan erhans cells are ant i enu w ards unt il t he become kerat inized and are shed. Lan erhans cells are ant i en--

presenting cells t hat have great import ance in t he imm unological react ions t hat occurpresenting cells t hat have great import ance in t he imm unological react ions t hat occuron the skin. Merkel cells are mechanoreceptors, t hat t ransmit neural impulses everyon the skin. Merkel cells are mechanoreceptors, t hat t ransmit neural impulses everyt ime t he skin is st ret ched. Melanocytes produce melanosomes, organelles t hat containt ime t he skin is st ret ched. Melanocytes produce melanosomes, organelles t hat containp gmen a con r u es o e co our o our s n.p gmen a con r u es o e co our o our s n.


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GSk13bGSk13b Melanocytes are dendrit ic cells, that is, they have branches, likeMelanocytes are dendrit ic cells, that is, they have branches, likea t ree. Melanosomes are roduced and mi rate t o t he t i of the cel la t ree. Melanosomes are roduced and mi rate t o t he t i of the cel l

branches. Kerat inocytes phagocytose t his t ipbranches. Kerat inocytes phagocytose t his t ip-- membrane, cytoplasmmembrane, cytoplasmand melanosomes together, and so acquir e pigm ent . Kerat inocytes areand melanosomes together, and so acquir e pigm ent . Kerat inocytes areunable t o make melanin themselves. Because melanosomes are insideunable t o make melanin themselves. Because melanosomes are insidephagosomes, the pigm ent is soon lysed by t he kerat inocyte lysosomes,phagosomes, the pigm ent is soon lysed by t he kerat inocyte lysosomes,so t hat t he cells of t he upper part s of t he epidermis, in Caucasians, showso t hat t he cells of t he upper part s of t he epidermis, in Caucasians, show

lit t le melanin.l it t le melanin.


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SC: stratum corneum, made of dead, keratinized cells;SC: stratum corneum, made of dead, keratinized cells;SL: stratum lucidum, seen on palms and soles;SL: stratum lucidum, seen on palms and soles;

, ,, ,containingcontaining f i laggrinfi laggrin, that aggregates the filaments of keratin to form the tough cells, that aggregates the filaments of keratin to form the tough cellsof the horny layer;of the horny layer;

, ,, ,polygonal cells are separated by "spinous" processes, which are, in fact,polygonal cells are separated by "spinous" processes, which are, in fact,

desmosomes;desmosomes;L: Lan erhans cell M: melanoc te BK: basal keratinoc te.L: Lan erhans cell M: melanoc te BK: basal keratinoc te.


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Histopathological Terms in pigmentedHistopathological Terms in pigmented

Junctional naevus.Junctional naevus.

..

Intradermal Naevus.Intradermal Naevus.

Melanoma in situ.Melanoma in situ...

Nodular Melanoma.Nodular Melanoma.Radial and Vertical Growth.Radial and Vertical Growth.


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AA AAsymmetrysymmetry

CC CColour Variationolour Variation

DD DDiameter (> 6iameter (> 6--7 mm)7 mm)

eva on or o u ar yeva on or o u ar y

Itchin and bleedin are lesserItchin and bleedin are lessersigns.signs.


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GSK13GSK13 A pigmented, elevated lesion, of uniform colour andA pigmented, elevated lesion, of uniform colour and

-- ..


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HSk02HSk02 Benign melanocytes are seen in the junction betweenBenign melanocytes are seen in the junction betweenepidermis and dermis, as well as deep in the dermis. Thisepidermis and dermis, as well as deep in the dermis. This

image corresponds to GSk 13, and is a compound naevus.image corresponds to GSk 13, and is a compound naevus.Because naevus cells tend to migrate into the dermis, how canBecause naevus cells tend to migrate into the dermis, how can

naevus, and malignant melanocytes of melanoma, which alsonaevus, and malignant melanocytes of melanoma, which alsotend to infiltrate the dermis?tend to infiltrate the dermis?


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Intra dermal Naevus.Intra dermal Naevus.

they occupy the dermal layer.they occupy the dermal layer.


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..

GSk15GSk15 ThisThispreauricularpreauricular

naevus isnaevus iselevated andelevated and

--coloured. Itcoloured. It

to anto anintradermalintradermalnaevus.naevus.


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HSk19HSk19 The beni nThe beni n

melanocyt es inmelanocyt es inthis int radermalt his int radermalnaevus are all innaevus are all in

t he derm isthe derm is-- t herethereare no nest s ofare no nest s ofnaevus cells at t henaevus cells at t he

epidermalepidermal--dermaldermalj unct ion. Thisj unct ion. Thisimage correspondsimage corresponds

to clinical pictureto clinical pictureGSk 15. There isGSk 15. There isscant y pigmentscant y pigment ..


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GSk17GSk17 A f lat pigmented lesion, ofA f lat pigment ed lesion, of

j unct ional naevus.j unct ional naevus.


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HSk18HSk18 Benign m elanocytes, or naevus cells, formBenign melanocytes, or naevus cells, formnests locat ed in t he junct ion betw een epiderm is andnests locat ed in t he junct ion betw een epiderm is and

derm is. This im age corresponds t o clinical picturederm is. This im age corresponds t o clinical pictureGSk 17, and is aGSk 17, and is aj unct ional naevus.j unct ional naevus.


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ma gnan

A largees on> cm,ass metrical

showing an

borderraised and flat

variable colour


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AssymetryAssymetry

Border Irre ularitBorder Irre ularitColour VariationColour Variation

..

cmcm

Bleeding had beenBleeding had beennotenote


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HSK01 This is malignant melanom a The cyt ologicalHSK01 This is malignant melanom a The cyt ologicalfeatures of mal i nanc are seen cel lu larfeatures of mal i nanc are seen cel lu lar

pleomorphism,; numerous mit oses) .pleomorphism,; numerous mit oses) .Not e : Radial and Vert ical grow thNot e : Radial and Vert ical grow thDepth ( Breslow ) in mm How do w e measure t hat ?Depth ( Breslow ) in mm How do w e measure t hat ?Heavy pigment at ion.Heavy pigment at ion.

..Lymphocyt ic react ion beneath t he melanoma.Lymphocyt ic react ion beneath t he melanoma.


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o repeat :Nest s of

ma gnantmelanomace s n t eepiderm is ra a grow tphase


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AndI nvasive

malignant

melanoma -verticalgrowth

Breslowmeasurement t o the

deepestme anomacell.


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..

s pa en was ns pa en was ncoma and developedcoma and developedbronchopneumonia,bronchopneumonia,

because of the difficult tobecause of the difficult toexpec ora e mucusexpec ora e mucuscontaining bacteria. Thecontaining bacteria. Thelung is congested, andlung is congested, andshows multifocal yellowshows multifocal yellowareas o pusareas o pus-- e a veoe a veo

surrounding bronchioles.surrounding bronchioles.


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ABCDE Checklist for Pigmented lesionsABCDE Checklist for Pigmented lesions

AA AAsymmetrysymmetry

BB BBorder Irregularityorder Irregularity

DD DDiameter (> 6iameter (> 6--7 mm)7 mm)

eva on or o u ar yeva on or o u ar y

Itchin and bleedin are lesserItchin and bleedin are lesser

signs.signs.


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..

GSk12GSk12. This is a. This is asuperf icial spreadingsuperf icial spreadingmelanoma. Note that t hemelanoma. Note that t helesion is flat , w it hlesion is flat , w it hirregular, blurred bordersirregular, blurred bordersan as a ame er oan as a ame er oabout 2cm Note thatabout 2cm Note that

there is an area ofthere is an area of

right edge of t he lesionright edge of t he lesionw ith f ibrosis in t hew ith f ibrosis in t he

..

int erpreted as being anint erpreted as being anarea of t umour regressionarea of t umour regression

immunological responseimmunological responseby the host t o the tumourby the host t o the tumour

a dense l m hoc t ica dense l m hoc t icinfi l tr at ion mayinfi l tr at ion maysomet imes be seen onsomet imes be seen onhistological examinat ionhistological examinat ionof some skin t umours,of some skin t umours,

including melanoma).including melanoma).


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GSk11GSk11 This is a nodular melanoma WhereasThis is a nodular melanoma Whereas


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GSk11GSk11 This is a nodular melanoma. WhereasThis is a nodular melanoma. Whereassuperf icial spreading melanomas stay rest r ict edsuperf icial spreading melanomas stay rest r ict ed

w it hin t he epiderm is for many months, and only laterw it hin t he epiderm is for many months, and only laterinvades t he derm is and becomes elevated, t heinvades t he derm is and becomes elevated, t heno u ar me anoma s e eva e rom e s ar . sno u ar me anoma s e eva e rom e s ar . sform of melanoma is fr equent ly misdiagnosed, soform of melanoma is fr equent ly misdiagnosed, so

deeply and give early m etastases.deeply and give early m etastases.


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GSk 16GSk 16 This is anThis is an at ypical m oleat ypical m ole, or, or dysplasticdysplastic naevus. I t isnaevus. I t is, ,, ,

c) some of the atypical naevi may t urn int o melanomas,c) some of the atypical naevi may t urn int o melanomas,w hereas t his change is very rarely seen in common naevi. Manyw hereas t his change is very rarely seen in common naevi. Many

--cent re, w hich is symmetr ic and of uniform colour , sur roundedcentre, w hich is symmetr ic and of uniform colour , sur rounded

by a pigmented rim , w hich has w ellby a pigmented rim , w hich has w ell--defined borders anddefined borders anduniform colour. The symmet ry, w elluniform colour. The symmet ry, w ell--defined borders excludedefined borders excludemelanoma.melanoma.


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First to regional nodes and theFirst to regional nodes and thecorrespon ing area s ou e c ec e incorrespon ing area s ou e c ec e inany suspicious pigmented lesion.any suspicious pigmented lesion.

Then haematogenously virtually anywhereThen haematogenously virtually anywhereu common yu common y , ., .

GB12GB12 This coronal sect ion of t he brain show sThis coronal sect ion of t he brain show s


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num erous black met ast ases of m elanoma, t hat varynum erous black met ast ases of m elanoma, t hat vary

one cent im etre. Because t he brain has no lymphat ics,one cent im etre. Because t he brain has no lymphat ics,

haematogenously.haematogenously.


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MelanomaMelanoma

Level ILevel I : Melanomas confined to the: Melanomas confined to the

outermost layer of the skin, theoutermost layer of the skin, the epidermisepidermis. Also. Alsocalled "melanoma incalled "melanoma in--situ."situ."

Level I ILevel I I : Penetration b melanomas into: Penetration b melanomas into

the second layer of the skin, thethe second layer of the skin, the dermisdermis..--

through the dermis, but are still containedthrough the dermis, but are still contained

.. Level V:Level V: Penetration of melanoma into thePenetration of melanoma into the

,,

into the third layer of the skin, the subcutis.into the third layer of the skin, the subcutis.


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Named for the physicianAlexander Breslow

who in 1975 observed that as the thicknessof the tumor increases, the chance of

. ,

thickness of the melanoma of less than. m me ers s assoc a e w a -year

survival of 97% of patients whereas atumour thickness of more than 8.0-

of 32%.


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Med 4 Pigmented Lesions of the Skin

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