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Skin and soft tissue > Pigmentation - physio, disorders, pigmented lesions > Flashcards

Pigmentation - physio, disorders, pigmented lesions Flashcards

1
Q

What is melanin and its function

A
  • Pigmented polymer
  • protects DNA from UV radiation (200-2400nm)
  • deactivates free radicals
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2
Q

What are the 3 types of melanin, location and production

A
  • Eumelanin (hair/skin)
    • Tyrosine ->(Tyrosinase) ->Eu-M
  • Pheomelanin (blond/red hair)
    • Tyrosine+cysteine ->(Tyrosinase) - >Pheo-M
  • Neuromelanin (Neural tissue)
    • unclear fx/production
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3
Q

How/Where is melanin made and distributed?

A

In melanocyte

  • melanin in made in ER, packed in Gogi and released into melanomsome
  • Melanosome is distributed to keratinocyte via dendritic processes of melanocyte

In keratinocyte

  • melanosome is phagocytized into keratinocyte, and incorproated to cell membrane surrounding nuclei
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4
Q

What are melanocytes, embryology, location in the body

A

Melanocytes are spindle cells that produce melanin

  • derived form neural crest cells in 10th wk GA
  • migrate to epidermis (s. basale), hair follicle, mucous membrane, dermis (then named nevus cells), neural tissue, eye, inner ear
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5
Q

What is a nevus cell - and how does it differ from melanocyte?

A
  • Nevus cell is a melanocyte whic hhas migrated into dermis
  • Differs from melanocyte in that the nevus cell is:
    • round/spindle (vs. dendritic)
    • located in dermis (vs. s. basale)
    • lives in clusters (vs. individual)
  • Similar to melanocyte in that the nevus cell
    • has small nuclei
    • mitoses are rare
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6
Q

What 4 pigments are responsible for skin color? (list chromophore)

A
  • Endogenous (melanocytes)->Brown w melanin
  • Exogenous (diet) ->Yellow/orange w carotene
  • Intravascular-> Blue w deoxyhemoglbin
  • Intravascular ->Red w oxyhemoglobin
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7
Q

What determines the skin pigment at baseline?

A
  • Density of melanosomes in the keratinocyte and the density of melanin in each melanosome
  • Balance of Eumelanin (brown-blakc) vs Pheomelanin (yellow-red)
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8
Q

What factors control the color of skin

A
  • Genetics
  • Hormonal control
    • melanotrophic hormones (MSH, ACTH, pregnancy, lipotropin)
  • UV - stimulates release of melanotrophics from keratinocytes which stimualtes melanocytes to produce more melanin
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9
Q

What are hypopigmentary disorders

A
  • Vitiligo
  • Albinism
  • Waardenburg
  • Leptomeningeal melanocytosis
  • Neurocutaneous melanosis
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10
Q

What is vitiligo

A

Hypopigment disorder with selective destruction of melnocytes in epidermis +/- follicles

  • Onset 10-30yo, progressive
  • sharply demarcated hypopigment macule which coalesce

Treatment

Non-op: Repigment with phototherapy, Depigment with hydroquinone, Tattoo

Operative: punch graft

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11
Q

What is albinism

A

Congenital hypopigmentary disorder - no production of melanin

  • Onset birth
  • No pigment in hair, eyes, skin
  • normal density of melanocytes
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12
Q

List types of Nevocellular Nevi

A

Acquired

  • Junctional nevus - at D-E jx
  • Compund nevus - in dermis and epidermis
  • Dermal nevus - in dermis only

Congenital

  • GCMN
  • Non-giant CMN

Special

  • Halo nevus
  • Spitz nevus
  • Atypical nevus
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13
Q

When do acquired nevocellular nevi appear, change with age?

A
  • Not present at birth
  • progress from junctional ->compound ->dermal
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14
Q

What is a giant CMN?

A
  • Pigmented nevus present at birth or shortly therafter, caused by abnormal migration of melanoblasts b/w 8-24th wk GA
  • link to c-met oncogene
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15
Q

How is GCMN defined clinically

A

>20cm dimater

50% of body region

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16
Q

What conditions are associated w GCMN

A
  • leptomeningeal melanocytosis
  • NF
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17
Q

What are treatment options for GCMN?

A

Medical

  • observe (dermoscopy/photo)
  • Laser
  • dermabrasion
  • chemical peel

Surgical

  • Serial excision, Tissue expansion, local flaps
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18
Q

What is the prognosis of GCMN

A
  • <4% malignant transformation , usually <age>
    </age><li>may lighten w age or nodular, hair growth</li>

</age>

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19
Q

If child presents w GCMN, what are RFs for associated neurocutaneous melanosis

A
  • GCMN on midline trunk/calvarium
  • seizures, abnormal CNS development
  • multiple satellite lesions

Workup for? neurocutaneous melanosis

MRI <6mths of age

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20
Q

What is a halo nevus?

A

Pigmented nevus w area of surrounding hypopigment

Treatment - expectant, excise if risk dysplastic nevus

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21
Q

What is a spitz nevus?

A

Benign Juvenile melanoma (spindle cell nevus of reed)

  • Epid: majority <30yo, acquired or congenital
  • Presentation; common H&N, symmetric small well circumscribed pigmented papule

Treatment

  • observe
  • excise if changes/cosmesis
22
Q

What differentiates spitz nevus, atypical spitz nevus, malignant spitz?

A

Histology

  • nest of spindle nevus cells in variable levels of dermis
23
Q

What is your DDx of a congenital nevus?

A
  • Nevis spillus
  • beckers nevus
  • acquired nevus
  • lentigo nevus sebaceous
  • mongolian spot
  • cafe au lait
24
Q

List benign melanocytic lesions

A

Epidermal

  • Ephelis
  • Lentigo
  • Cafe au lait
  • becker nevus

Dermal

  • Blue nevus
  • mongolian blue spot
  • Nevus of Oto/Ito
25
What is lentigo pathology, types and presentation
* increased melanocytes in basal layer * Lentigo simplex (younger pt) associated w LEOPARD, LAMB, PEutz Jagher * Solar lentigo due to sun * Malingna lentigo
26
What is an ephelide, pathology and presentation, treatment
Melanocytic lesion in the epidermis * increased melanin, normal # melanocytes * decrease in number w age Tx - laser, cryo
27
What is a Cafe au lait spot
Benign melanocytic lesion of the epidermis * increased # melanocytes + acanthosis * looks alike large brown patch * present at birth, fades w age
28
What is a becker nevus
Benign HAIRY melanocytic lesion in ther epidermis * increase #melanocytes and melanin granules * appears in M, at puverty +/- hair, on back/shoulder, submammary Treatment - depilation, laser may lighten
29
What is a nevus spillus
Lentigo simplex ( melanocytic lesion in the epidermis) + smaller darker papule/macule
30
What is associated w cafe au lait spots
* McCune albright * NF 1/2
31
What is your DDx for a pigmented macule \<1cm
* Lentigo (solar) * lentigo implex * lentigo maligna * LEOPARD syndrome * LAMB syndrome * Peutz Jeghers * dysplastic nevus * junctional nevus
32
What is the tyndall effect
Red (long) wavelengths pass by melanin but the shorter wavelengths (blue) are scattered, with some going back to skin surface
33
What is a mongolian spot
Congenital melanocytic lesion in dermis * increased # of melnaocytes * caused by abnornal migration of neural crest cells * located in sacrococcygeal region, most common in hispanic, asian, native american * uniform blue gray well demarcated lesion * FADE by 3-4yrs of age
34
What is Nevus of ota and nevus of Ito
COngenital melanocytic lesion in the dermis * located in 1st or 2nd branchial arch (Oto) * or located on shoulder, deltoid, supraclav (Ito) * occur at birth OR puberty, F:M * confluence of blue black macules w associated brown spots Treatment Q-switched laser or NdYAG laser
35
What is Hori's Nevus
Congenital melanocytic lesion in dermis * looks like Nevus of Oto but bilateral and apepars in 40-50yo asians
36
What is a blue nevus
Congenital melanocytic lesion in dermis * blue raised papule - may arise at any age * increased # of melnocytes * MM can arise from blue nevus * Assocaited with syndrome LAMB if multiple present * Lentiges * Atrial myxoma * Mucocutaneous myxomas * blue nevi * TREATMENT * excise if \>10mm or changing- margin 3-5mm
37
What is ur DDx of a blue nevus
* Nodular melanoma * Cutaneous melanocytic melanoma * Kaposi sarcoma * Venous malformation
38
What are premalingnat lesions for melanoma
* GCMN * Lentigo melanoma * MIS * atypical/dysplastic nevus
39
What is the histology of dysplastic nevus?
* discontinuous priliferation of atypical melanocytes with nest formation intraepidermal
40
What is the risk of melanoma from dyspalstic nevus?
* DN is a RF for development of melanoma * DN is also a precursor for melanoma - 1/40 000 transform
41
What is lentigo malingna and te pahtology
COnsidered melanoma in situ on sun damaged skin Path * non-nested proliferation of atypical melanoctyes in an atrophic epidermis Prognosis * up to 30% trasnform into MIS, LMM or desmoplastic melanoma
42
WHat is MIS
Intraepidermal proliferation of atypical melnocytes w fully evolved atypia * most commonly melanoma arises form MIS
43
What is FAMM
Familial Atypical Mole and Melanoma syndrome * FDR or SDR with MM * \>50 nevi * AD inheritance Prognosis * 10% risk of melanoma over 10yrs
44
What are syndromes associated with melanocytic lesions
* FAMM * Waardenburg syndrome * ALbright syndrome * LAMB syndrome * LEOPARD syndrome * Peutz Jegher syndrome * Central facial lentiginous
45
What is waardenburng syndrome
Congenital ABSENCE of melanocytes in hair, skin, ears, stria vascularis of ear Associated w CL/P 7% AD, due to defect in migration of NCC and melanin synthesis **Clinical features** * Skin; patchy hypo and hyperpigmented patches * Hair:premature greying/white forelock * Ear: SNL * Eye: heterochromia, isohypochromia (pale blue), blepharophimosis, telecanthus
46
What is albright syndrome
Unilatreal polyostotic FD with cafe au lait spots and hyperfunctional endocrinopathies
47
What is LEOPARD syndrome
* Hypertelorism * lentigo * pulmonary stenosis * genital abnormalities * deafness
48
What is peutz jegher
* intestinal polyposis * mucosal lentigo
49
What is LAMB syndrome
* Lentigo * Atrial myxoma * Mucocutaneous myxoma * Blue nevi
50
What is centrofacial lentiginosous
* LEntigo simplex in horizontal band across face * craniofacial microsomia * CLP
51
What is epidermal nevus syndrome
* Craniofacial overgrowth * Digital gigantism * acquired nevocellular nevi * Vascular mlaformations (CNS or cutaneous)
52
What is Neurocutaneous melanosis (= leptomeningeal melanocytosis)
Def. Nevocellular infiltrate into leptomeninges and brain parenchyma **Clinical features** * **hydrocephalus** * **seizure** * **focal neurologic deficits** Presents around 2yr RFs - GCMN - Congenital nevocellular nevus at midline on scalp, neck, spine Do MRI before 6mths Treatment - symptomatic. Delay excision due to poor prognosis Prognosis * asymptomatic: 60% risk of leptomeningeal melanoma (90% fatal) * symptomatic (90% mortality)

Skin and soft tissue (13 decks)

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