Derm patho Flashcards
1
Q
What are the functions of the skin?
A
Barrier against microorganisms, ultraviolet radiation, loss of body fluids, and the stress of mechanical forces
Regulates body temperature
Involved in the production of vitamin D
Touch and pressure receptors provide important protective functions and pleasurable sensations
2
Q
What is the deepest layer of the skin and what is its function?
A
Stratum basale: Location of mitosis for keratinocytes, melanocytes, merkel cells
3
Q
What is the 2nd layer of the skin and what is its function?
A
Stratum spinosum: new keratinocytes (desmosomes)
4
Q
What is the 3rd layer of the skin and what is its function?
A
Stratum granulosum: granular layer with keratohyaline granules
5
Q
What is the 4th layer of the skin and what is its function?
A
Stratum lucidum: Keratinocytes
6
Q
What is the 5th layer of the skin and what is its function?
A
stratum corneum: contains anucleate cells with keratin
7
Q
What is the stratum basale AKA?
A
stratum germinativum
8
Q
What do squamous epithelial cells produce?
A
Produce keratin protein and cytokines
9
Q
what are melanocytes derived from
A
neural crest cells in the ectoderm
10
Q
what are melanosomes?
A
synthesize melanin
11
Q
what is melanin derived from
A
Tyrosine(AA from phenoalanin) to DOPA (by tyrosinase)
DOPA to melanin
12
Q
what is PKU
A
disorder where you cant metabolise phenoalanine=cant produce melanin= pale/albino
13
Q
what is different in melanin between AA and whites?
A
Number of melanocytes is the same in all races
Melanin degraded more rapidly in whites
Whites: melanosomes concentrated in basal layer
AA: melanosomes present throughout all layers
AA: Melanocytes are larger with more dendritic processes
14
Q
Where do Langerhan dendritic cells come from and where are they located
A
bone marrow derived
migrate to epidermis and lymph nodes (uncommonly to dermis)
15
Q
what is the role of Langerhan cells
A
regulate contact hypersensitivity and self recognition(graft vs host rejection) by expresion of MHC1, MHC2, and FC igG and IgE receptors
16
Q
how do steriods affect Langerhans cells
A
slow down their function
17
Q
what are merkel cells associated with
A
terminal neuronal axon
18
Q
what body locations are merkel cells typically found
A
specialized regions such as lips, oral cavities, palmar skin
19
Q
where is the greatest amount of eccrine glands located
A
distributed over the body with greatest number on face, chest, and back
20
Q
what do eccrine glands release and what is their funciton
A
salt water, regulates body temp
21
Q
what do apocrine glands release
A
salt water and other chemicals
22
Q
where do hair follicles originate from
A
originate in the primitive epidermis but grow downward to the matrix located in the deep dermis
23
Q
what is the dermis composed of
A
Collagen, elastin reticulum, gel-like ground substance
24
Q
what structures are present in the dermis
A
Hair follicles, sebaceous glands, sweat glands, blood vessels, lymphatic vessels, nerves
25
what cells are present in the dermis
Fibroblasts, mast cells, macrophages
26
what is the papillary dermis
Loose CT layer dirctly beneath the epidermis
27
what is the reticular dermis
lower dermal layer composed of dense dermal collagen (continuous with subcutaneous collegen)
28
what is the function of collagen layers seperating adipose layers
helps with heat regulation
29
what are the 4 structural units of the nail
The matrix from which the nail grows
The hyponychium (nail bed)
Nail plate
30
how much does the nail grow in a day
1mm or less
31
what are Cutaneous lymphocyte associated antigens(CLA)
Expressed on the memory T cells to Mediates cutaneous inflammatory and infectious diseases
32
what skin layer is know as the horny layer
stratum corneum
33
what are the changes to skin associated with aging
Atrophy of sebaceous, eccrine, and apocrine glands
Changes in hair color
Fewer hair follicles and growth of thinner hair
34
what are macule characteristics
Flat
Distinguished by coloration
Patch: flat irregular shaped macule >1cm diameter
35
what are papule characteristics
Elevated
Domed shape or flat topped
1 cm or less across (Nodule is greater than 5mm
36
what are Plaque characteristics
Elevated
Flat topped
Usually greater than 1cm across
37
what are vesicle characteristics
1 cm or less across
Bulla is greater than 1cm (Blister)
Blister is common term for Vesicle and Bulla
38
what are wheal characteristics
```
Itchy
Transient
Elevated lesion
Variable blanching
Erythema due to dermal edema
```
39
what are scale characteristics
Dry
Horny
Plate like
Imperfect cornification
40
what are charcacteristics of lichenification
Thickened rough skin
| Prominent skin markings (due to repeated rubbing)
41
what is onycholysis
separation of nail plate from nail bed
42
what is excoriation
Traumatic lesion breaking the epidermis
| Raw linear area (deep scratch)
43
what is hyperkeratosis
Thickening of stratum corneum
| Qualitative abnormality of the keratin
44
what is parakeratosis? Where is it normal?
Keratinization with retained nuclei of the stratum corneum
| Normal on mucous membranes
45
what causes retained nuclei
improper maturation
46
how can radiation affect the epidermis
can cause hyperkeratosis
47
what is hypergranulosis
Hyperplasia of stratum granulosum
| Usually due to rubbing
48
what is acanthosis
Diffuse epidermal hyperplasia
49
what is papillomatosis
Surface elevation caused by hyperplasia and enlargement of contiguous dermal papilla
50
what causes cafe au lait macule
increased melanogenesis
51
what is cafe au lait associated with
neurofibromatosis
52
what is beckers nevus
solitary lesions that break up into smaller macules at the periphery
53
what is dermal melanocytosis and how does it appear
condition where melanocytes are found in the dermis and actively synthesize melanin. A blue color is given off from shorter wavelengths(Tyndall effect)
54
what conditions have dermal melanocytosis
mongolian spots, nevus of ota and ito
55
how are nevus of ota/ito similar
congenital: apparent within 1st year of life
apperaance: mottled
asians and AA
56
how are nevus of ota/ito different
divisons
| Ito: Posterior supraclavicular and lateral brachiocutaneous nerves
57
what is acantholysis and what is an example of it
Loss of intercellular cohesion between keratinocytes
| Pemphigus vulgaris-chronic blistering skin condition
58
what is spongiosis
Intracellular edema of the epidermis
59
what is hydropic swelling(or ballooning)? When does it occur?
Intracellular edema of keratinocytes
| Seen in viral infections
60
what is exocytosis
Infiltration of epidermis by inflammatory cells
61
what is erosion
incomplete loss of the epidermis
62
what is ulceration
Complete loss of the epidermis revealing dermis(bleeding)
63
what is vacuolization
Formation of vaculoes within or adjacent to cells
64
what is lentiginous
linear pattern of melanocyte proliferation within epidermal basal layer
65
what are nested melanocytes
the melanocytes are clumped together (not in linear pattern like lentiginous)
66
What is vitiligo and what causes it?
Depigmentation from Autoimmune,Genetic,Oxidative stress(surgery)
67
What is the diff bt segmented and non-segmented vitiligo?
Non-Segmented
Most common, at any age, symmetry
Segmented
Aggressive, dorsal root presentation
68
what are freckles caused from?
Increase amount of melanin within basal keratinocytes
| Melanocytes may be slightly enlarged but normal density
69
how are lentigo diff from freckles
Benign localized hyperplasia of epidermal melanocytes (freckles don’t increase #)
Do not darken with sunlight
70
T/F lentigo involves skin and mucous membranes
T
71
what is melisma, where is it located, and what causes it
Dark, irregular, well demarcated, hyperpigmented macules to patches
Location: upper cheek, nose, lips, upper lip, and forehead.(mask of preg)
Stimulation of melanocytes or pigment-producing cells by estrogen and progesterone to produce more melanin pigments when exposed to sun
72
what is the melanocyte nevus size ranking
Size(2.0
73
are nevi more commonly acquired or congenital
Can be both, acquired more common
74
how are nevus cells(type of melanocyte) diff from epidermal melanocytes
Nevus cells cluster as nests within the lower epidermis and/or dermis
Nevus cells do not have dendritic processes
Epidermal melanocytes are evenly dispersed
75
what are the earliest types of nevi and what is characteristic of them
Junctional
Located along the dermoepidermal junction in nests
Nuclei uniform
Little or no mitotic activity
76
what do junctional nevi progress to
Compound-growth from dermoepidermal junction to underlying dermis
77
what do compound nevi progress to?
Intradermal- they have no epidermal nests
78
What does activation of RAS gene do
Increases proliferation of melanocytes
79
what is the role of BRAF
encodes serine/threonine kinase
| Positive mediator of RAS signals=increases proliferation of melanocytes
80
what is the effect of a mutated BRAF
Mutation causes it to be always activated= increases proliferation of melanocytes
81
what does the CDKN2A(p16) gene do
turns off CDK4= dec melanocyte proliferation
82
what are characteristics of dysplastic nevus
Larger than acquired nevi (> 5mm)
Flat macules, slightly raised plaques or target like lesions with darker raised center (pebbly surface)
Irregular flat periphery
Variability in pigmentation (Variegation)
Irregular borders
Usually compound
83
what is cytologic atypia
irregular cells- irregularly shaped, dark staining nuclei
84
what is the effect of a mutated CDKN2A(p16)
normally it is a cyclin dependent kinase inhibitor to inhibit CDK4 kinase= stop proliferation.
Mutation= proliferation
85
what are the sites of origin:
skin, oral, anogenital mucosal surfaces, esophagus, meninges, eye
86
when does malignant melanoma typically become resistant to therapy?
once it metastasizes
87
what are the deadly skin Ca
malignant melanoma
| Rarely Merkel cell tumor
88
does malignant melanoma grow vertical or horizontal?
both
89
what is lentigo maligna
indolent melanoma on face of elderly
90
what are acral lentiginious
malignant melanoma with radial growth unrelated to sun exposure (trunk, anogenital, sinus)
91
what gender has a worst prognosis for malignant melanoma
males
92
why do malig melanoma on extremities have a better prognosis than the trunk
people see them faster
93
what are prognostic factors of malig melanoma
Tumor depth (Breslow thickness)
Number of mitoses
Evidence of tumor regression (presumably due to host immune response)
Presence and number of tumor infiltrating lymphocytes
94
what depth of malig melanoma has a "good" prognosis
<1.7mm (clarks level 1 or 2)
95
what is the role of the p14ARF gene
inhibits MDM2=inc p53
96
what is the role of the MDM2 gene
inhibits p53= inc survival of melanoma cells
97
what are benign epidermal tumors derived from
keratinizing stratified squamous epithelium of the epidermis, hair follicles, and ductular epithelium of cutaneous glands
98
what is a fibroepithelial polyp
skin tag
99
what is seborrheic keratosis
Round, flat, coin-like, waxy plaques
Vary in diameter from mms to cms
Uniformly tan to dark brown
Velvety to granular surface
100
how do you differentiate seborrheic keratosis from malig melanoma
hand lens will reveal Small, round, porelike ostia impacted with keratin
101
what is the path report of sevborrheic keratosis
Keratin filled horn cysts, some communicate with surface (pseudo-horn cysts)
102
what is dermatosis papulosa nigra
multiple small SK lesions on face due to keratin deposition in epidermis
103
what is the pathogenesis of SK
Mutation in FGFR3 gene
Fibroblast growth factor receptor-3
Drives the growth of the tumor
104
what is paraneoplastic syndrome
disease or symptom that is the consequence of the presence of cancer in the body, but is not due to the local presence of cancer
ie explosively large numbers of SK can result from inc ADH from a tumor or stimulation of transforming growth factor alpha(GI carcinoma)
105
what is the Leser-Trelat sign
explosive onset of multiple seborrheic keratoses
106
what are characteristics of benign acanthosis nigricans
80% of cases
Develops gradually
Occurs in childhood or during puberty
Various presentations
Autosomal dominant with variable penetrance
In association with obesity or endocrine abnormalities (pituitary or pineal tumors, and diabetes)
Part of several rare congenital syndromes
107
what are characteristics of malignant acanthosis nigricans
Arise in middle aged or older individuals
| Occurs in association with underlying cancers(GI adenocarcinomas)
108
what is the morphology of acanthosis nigricans
Numerous repeated peaks and valleys in epidermis
Variable hyperplasia
Slight basal cell layer hyperpigmentation (no melanocyte hyperplasia)
109
what is the pathogenesis of acanthosis nigricans
Familial form associated with FGFR3
May be an isolated finding or seen together with skeletal deformities
Achondroplasia (mutation in FGFR3)
Thanatophoric dysplasia(mutation in FGFR3)
110
what is a fibroepithelial polyp
skin tag
111
what is the morphology of fibroepithelial polyps
Fibrovascular cores
Covered by benign squamous epithelium
Can undergo ischemic necrosis due to torsion
112
what disorders are fibroepithelial polyps associated with
Diabetes
Obesity
Intestinal polyposis
113
what lesions become more numerous or prominant during preg
fibroepithelial polyps, melanocyte nevi, hemangiomas due to hormones
114
what is a epidermal cyst and what is does it form
Invagination & cystic expansion of epidermis or hair follicle
Cyst filed with keratin and lipid debris from sebaceous secretions forming a wen
115
what are characteristics of a epidermal (inclusion) cyst
```
Dermal or subcutaneous
Well circumscribed
Firm
Often moveable nodules
Can undergo traumatic rupture and be expressed
```
116
what is the wall and center like in epidermal inclusion cyst and how does this differ from pilar or trichilemmmal cysts
Epidermal inclusion cyst
Wall: Resembles normal epidermis
Center: Filled with laminated strands of keratin
Pilar or trichilemmal cysts
Wall: Resembles folliclular epithelium without granular cell layer
Center: Filled with homogenous mixture of keratin and lipid
117
what is the wall like for Dermoid cyst
Similar to epidermal inclusion with multiple appendages budding outward
118
what is steatocystoma simplex
Resembling sebaceous gland duct from which numerous compressed sebaceous lobules originate
119
what is steatocystoma multiplex
different than steatocystoma simplex. caused by a missense mutation in keratin
120
what are adnexal appendage tumors
BENIGN but confused with basal cell carcinoma
121
what is the inheritance pattern of adnexal appendage tumors
some have mendelian pattern of inheritance causing a predisposition for internal malignancy
122
what type of structures do adnexal appendage tumors involve
HAIR FOLLICLES
SEBACEOUS GLANDS
SWEAT GLANDS
123
what are characteristics of adnexal tumors
```
Appendage tumors
Flesh colored
Solitary or multiple
Papules and nodules
Some have predisposition for specific body surfaces
```
124
what is a eccrine poroma
adnexal tumor on palms and soles
125
what is cylindroma
adnexal tumor of the forehead and scalp
126
what is the pathogenesis of cylindroma
dominantly inherited causing inactivation mutation in TSG CYLD
Islands of cells resembling normal epidermal or adnexal basal cell layer
Fit together like jigsaw puzzle
127
what is trichoepithelioma and what is the pathogenesis
adnexal follicular tumor
| Proliferation of basaloid cells that forms primitive structures resembling hair follicles
128
what are syringomas
adnexal tumor of eccrine glands forming Multiple small tan papules in lower eyelids
129
what are sebaceous adenomas associated with
Associated with internal malignancy in Muir Torre syndrome (a subset of hereditary nonpolyposis carcinoma syndrome)
130
what are characteristics of actinic keratosis and what causes it
```
Dysplastic changes prior to carcinoma
Sun damaged skin
Other causes
Ionizing radiation
Industrial hydrocarbons
Arsenicals
Exhibit heperkeratosis
Lightly pigmented individuals.
```
131
what is the hallmark sign of actinic keratosis
Parakeratosis-corneum cells retain nuclei
132
what are the lesions like in actinic keratois and where are they located
```
Lesions
Most are <1m
Tan-brown, red or skin colored
Rough sandpaper like
Cutaneous horn
Locations: sun exposed sites
```
133
what is actinic chilitis
keratosis on the lips
134
what is the pathogenesis of actinic keratosis
cytologic atypia in lower most layers of epdermis. May be associated with hyperplasia of basal cells
135
what is imipuimod
med that activates immune system by stimulating Toll-like receptors. used for actinic keratosis or SCC
136
what are the most common tumors from sun exposure
1st=basal cell carcinoma
| 2nd= squamous cell carcinoma
137
does SCC metastasize to nodes
Yes but <5%
138
what is the morphology of SCC in situ (Bowen's disease)
no invasion through dermatoepidermal junction
Sharply defined, red, scaling plaques
Involves all levels of epidermis
139
what is the morphology of advanced SCC
Invasive and nodular: variable degrees of differentiation
Variable keratin
May ulcerate
140
what is the pathogenesis of SCC
UV light damages DNA p53. P53 is normally upregulated by kinases(ATM and ATR) but not if mutated p53.UV also dec immune surveillance
141
besides UV, what else increases SCC risk
immunosuppression (chemo, organ transplants), HPV 5 and 8, steriods
142
besides UV what else inc BCC risk
immunosuppression,
143
what is xeroderma pigmentosum
inherited defects in DNA repair(both PTCH and p53. Cannot be exposed to sun at all
144
what are blue palisading nests
cells line up and squish together. only seen in BCC
145
what are characteristics of BCC lesions
Pearly papules
Prominent dilated subepidermal blood vessels(telangiectasias)
May contain melanin
146
what are characteristics of advanced BCC lesions
ulcerate, local invasion of bone or facial sinuses
147
what is the morphology of BCC
Tumor cells resemble normal basal cell layer of epidermis
Arise from epidermis or follicular(deeper) epithelium
2 patterns(multifocal growths and nodular lesions)
148
what is characteristic of multifocal BCC growths
Originate from epidermis
| Extend over several square cms
149
what is characteristic of nodular BCC lesions
grow downward into dermis
150
what is the pathogenesis of Nevoid BCC(gorlin syndrome)
Autosomal dominant: Chr9, PTCH gene mutation
2nd normal allele becomes inactivated by UV light.
PTCH gene encodes a receptor for Sonic Hedgehog gene(normally prevents BCC)
Absence of PTCH causes activation of SMO which leads to basal cell carcinoma
151
what is the genetic component of Non NBCCS
Genetic component
30% have PTCH mutation
40-60% have p53 mutation
Xeroderma pigmentosa: defects in PTCH and p53
152
what is merkel cell carcinoma
VERY MALIGNANT AND LETHAL, LOOK LIKE SMALL CELL CA. OF LUNG
153
what are acute dermatoses
urticaria, eczema, erythema multiforme
154
what are chronic dermatoses
psoriasis, seborrheic dermatitis, lichen planus, lupus erthymatosus
155
what causes urticaria
Localized Mast Cell degranulation from IgE=Hist release=Dilation of vessels and Increase vascular permeability
156
what is the diff bt angioedema and urticaria
Angioedema is closely related to urticaria but characterized by deeper edema of both the dermis and subcutaneus fat.
157
what is ASA effect on urticaria
ASA blocks COX path so inc leukotriene path=inc hist release= inc urticaria
158
what is hereditary angioneurotic edema
inherited deficiency of C1 inhibitor(normally dec complement activation preventing Hist release) causes a complement mediated urticaria (in a majority of cases there is no cause)
159
why does IgE have more SE than IgG
```
IgG= activate macrophage and neutrophiles
IgE= activeate mast cells=hist release= more SE than IgG
```
160
what may cause persistent urticaria
collagen vascular disorder, hodgkin lymphoma
161
what are characteristics of eczema
red, papulovesicular, oozing, and crusted lesions.
| If persistent develop into raised, scaling plaques due to acanthosis and hyperkeratosis
162
what cells in the epidermis have a central role in contact dermatitis
langerhan cells
163
what is the pathway of eczema causing chronic lesions
A: initial dermal edema and perivascular infiltration by inflammatory cells. Is followed within 24-48 hours by
B: epidermal spongiosis and microvesicle formation
C: Abnormal scale along with acanthrosis
D: Hyperkeratosis
E: Chronic lesion
