high yield Skin path Flashcards
a melanocytic nevus (typical mole) has activating mutation in what?
RAS or BRAF
Dysplastic nevus syndrome what mutation
LOF of CDKN2A (encoding p16/INK4a)
-or CDK4
where are lesions in dysplastic nevus syndrome
sun exposed AND protected areas
highlights for Acrol lentiginous melanoma
- Flat
- DARK SKINNED individuals
- soles, palms, under nails
- C-Kit mutations
what melanoma is worst type
nodular due to vertical growth
Dermal neurotization is helpful in distinguishing this entity from melanoma
benign nevi
Melanoma cell stain
HMB 45
mutation for Seborrheic keratosis
Gof in FGFR3
SCC of skin is usually related to sun exposure but what is 2nd most common
immunosuppression so transplant or HIV
Morphology for SCC of skin
- hyperkeratosis
- Enlarged nuclei
- Keratin pearls
- Intercellular bridges
what is needed to confirm a diagnosis of SCC of skin
immunohistochemical stains for keratins
pearly nodules with tealangiectasias
BCC
BCC have mutations that lead to what
hedgehog signaling
-PTCH (SHH receptor) common
morphology for BCC
- ulceration of lesions
- palisading
- resemble the basal cell layer of epidermis
- multifocal
- nodular
inflammatory infiltrates in Acute inflammatory dermatoses
lymphocytes and macrophages rather than neutrophils
what are the 3 acute inflammatory dermatoses
- Urticaria (Hives)
- Acute Eczematous Dermatitis
- Erythema Multiforme
Which acute inflammatory dermatoses?
- edema of deeper dermis and subcutaceous fat
- mast cells
- NOO changes in epidermis
Urticaria
morphology of Urticaria
- circular plaques
- spaces between collagen bundles wider than normal
- dermal edema
Mast cell dependent, IgE independent Urticaria is from what
- opiates
- certain antibiotics
- curare
- radiographic contrast media
what are the 2 mast cell independent, IgE independent Urticaria talked about
- Aspirin
- Hereditary angioneurotic edema . caused by deficiency of C1 inhibitor
Eczematous dermatitis typically results from what type of reaction
-T cell mediated inflammatory reaction (type IV) hypersensitivity
what cells in the epidermis play a role in Eczema
Langerhans cells . .present haptens to CD4 cells
this is characterized by red, papulovesicular, oozing, and crusted lesions that if persistent, develop reactive acanthosis and hyperkeratosis that produce raised scaling plaques
Eczema
this is characterized by keratinocyte injury mediated by skin homing CD8+ cytotoxic T lymphocytes
Erythemia multiforme
what is the characteristic lesion in Erythma multiform
target like lesions
febrile form of erythema multiform associated with extensive involvement of skin (<10%).
-tends to involve lips, oral mucosa, conjunctiva, urethra, and genital and perianal areas
Stevens Johnson syndrome
This variant of Erythema multiform is characterized by diffuse necrosis and sloughing of cutaneous mucosal epithelial surfaces
-Widespread epidermal damage produces clinical picture similar to that seen in pts with extensive burns
Toxic epidermal necrolysis (>30% detached epidermis)
what are the chronic inflammatory Deratoses?
- Psoriasis
- Seborrheic Dermatitis
- Lichen Planus
well-demarcated, pink to salmon colored plaque covered by loosely adherent silver white scale
Psoriasis
what is the general basis of Psoriasis
autoimmune
Auspitz sign: minute bleeding points when scale is lifted from plaque
Psoriasis
morphology for psoriasis
- Nail changes
- the stratum granulosum is thinned or absent and extensive overlying parakeratotic scale is seen
- Neutrophilc in spongiotic foci of superficial epidermis (spongiform pustules)
- Munro microabscesses
where is Seborrheic dermatitis found
sebaceous glands but is still due to inflammation of epidermis
- scalp
- external auditory canal
- retroauricular
- nasolabial folds
- presternal
what other conditions are associated with Seborrheic dermatitis?
- Parkinson Disease
- Fungal species of Malassezia
- HIV with low CD4 counts
follicular lipping
Seborrheic Dermatitis
6 P’s for Lichen Planus
- Pruritic
- purple
- polygonal
- planar
- papules
- plaques
Koebner phenomenon is found in what conditions
- Lichen Planus
- psoriasis
- means induced by local trauma
Wickham striae: papules highlighted by white dots or lines
Lichen planus
Lichen planus is a prototype example of what
interface dermatitis
Colloid or Civatte bodies
Lichen planus
Honey colored crust
impetigo
characteristic microscopic feature of impetigo
accumulation of neutrophils beneath the stratum corneum
a blistering disorder caused by autoantibodies that result in the dissolution of intercellular attachments within the epidermis and mucosal epithelium
Pemphigus
pemphigus are what antibodies?
against what
- IgG
- Desmogleins
what is the characteristic finding by immunofluorescence of Pemphigus
net like pattern of intercellular IgG deposits
what is the common histologic denominator in all forms of pemphigus
-Acantholysis: the dissolution or lysis of the intercellular bridges that connect squamous epithelial cells
what type of blister is pemphigus VULGARIS
suprabasal acontholytic
highlights for Bullous Pemphigoid
- elderly
- inner thighs, flexor surfaces of forearms,axillae, groin, lower abdomen
- autoantibodies that bind to proteins that are required for adherence of basal keratinocytes to basement membrane
what type of blister is bullous pemphigoid
- Subepidermal nonacantholytic
- does not rupture easily
highlights for Dermatitis herpetiformis
- urticarial and grouped vsicles
- predominantly males
- third or fourth decade
- some cases associated with intestinal celiac disease and responds to gluten free diet
- Granular IgA deposits at tips of dermal papillae
Epidermolysis Bullosa highlights
- inherited structural protein defects
- blisters at sites of pressure, rubbing, or trauma at or soon after birth
What are the cutaneous lesions found in Tuberous sclerosis complex
- angiofibromas
- localized leathery thickenings (shagreen patches)
- Hypopigmented areas (ash-leaf patches),
- Subungual fibromas
Eccrine poroma
-palms and soles where sweat glands are numerous
multiple small tan papules in vicinity of lower eyelids
syringomas
appendage tumor on forehead and scalp, hat like growth
cylindroma
composed of factor XIIIa-positive dermal dendritic cells
benign fibrous histiocytomas (Dermatofibroma)
molecular hallmark for dermatofibrosarcoma protuberans
-translocation of COL1A1 and PDGFB
Morphology for Benign fibrous histeocytome (dermatofibroma)
psuedoepitheliomatous hyperplasia
Morphology for Deratofibrosarcoma protuberans
- blades of pinwheel fibroblasts (storiform)
- honeycomb patten
- Sezary Lutzner cells
- Pautrier microabscesses
Mycosis Fungoides (Cutaneous T cell lymphoma)
spectrum of rare disorders characterized by increased numbers of mast cells in the skin
Mastocytosis
Darier sign: localized area of dermal edema and erythema (wheal) that occurs when lesional skin is rubbed
Mastocytosis
Dermatographism: area of dermal edema resembling a hive that occurs as a result of localized stroking of apparently normal skin with a pointed instrument
Mastocytosis
osteoporosis in premenopausal women or men can be a clue for diagnosis of what
mastocytosis
Gene involved in acanthosis nigricans
FGFR3
Gene involved in Seborrheic Keratoses
FGFR3
