Skin Flashcards
1
Q
What percentage of body weight does the skin make up?
A
20%
2
Q
fxn of fibroblasts
A
lay down collagen, make skin rough
3
Q
fxn of perivascular mast cells
A
degranulate, increase vascular permeability
4
Q
fxn of dendrocytes
A
processing cells for anything that gets in the skin
5
Q
In what layer do you find new keratinocytes with desmosomes?
A
stratum spinosum
6
Q
In what epidermal layer will you find keratohyaline granules?
A
stratum granulosum
7
Q
What is a dermatophyte infection and in what epidermal layer will you see this?
A
fungal infection that lives off decaying cells, will find in the stratum corneum layer
8
Q
Cells in the epidermis
A
Keratinocytes, melanocytes, Langerhaan’s cells and dendrocytes, and merkel cells
9
Q
What is “dermabrasion”?
A
getting dead cells off of the epidermis, from the corneum layer
10
Q
Keratinocytes are squamous epithelial cells that can produce what?
A
Keratin and cytokines at times of injury
11
Q
Melanocytes are derived from?
A
neural crest cells
12
Q
Melanocytes are found in stratum?
A
basale
13
Q
Why will people with PKU have very pale skin?
A
because they can’t process phenylalanine (can’t convert to tyrosine which is needed to produce melanin)
14
Q
Besides production of melanin, what is tyrosine also important for?
A
catecholamine production
15
Q
How is melanin formed?
A
comes from tyrosine being converted to DOPA by tyrosinase and then DOPA can be converted to melanin
16
Q
Does the number of melanocytes differ between races?
A
NO!
17
Q
What is responsible for AA to have more pigmented skin?
A
Whites have much faster melanin degradation and their melanosomes are concentrated in the basal layer, AA have melanosomes present throughout the skin layers and have larger melanocytes with more dendritic processes.
18
Q
What is meant when you refer to Langerhaan’s cells as “immigrant cells”?
A
They are bone marrow derived, not formed embryonically but come from monocytes and migrate to the skin
19
Q
Where are langerhaan’s cells prevalent? Where are they uncommonly found?
A
prevalent in the dermis, uncommon in epidermis
20
Q
What cells play a role in contact hypersensitivity?
A
Langerhaan’s cells
21
Q
Describe type IV hypersensitivity
A
No Abs involved, it is an altered T cell response, cytotoxic T cells go crazy and over respond to a noxious stimulus (poison ivy, perfume)
22
Q
What specialized receptors/antigens to Langerhaan’s cells have?
A
They express MHC-1, MHC-II, Fc IgG, IgE receptors
23
Q
What cells act like mast cells in the lower epidermis and dermis?
A
Dendrocytes
24
Q
What is role of dendrocytes?
A
Can release histamine and contribute to the inflamm. response in the lower epidermis and in the dermis are involved in processing antigens
25
Why can people who come down with GVHD after a bone marrow transplant have skin discoloration and discoriation?
The langerhaan's and dendrocytes are processing the graft cells and the proteins the graft cells are now producting, causing a skin reaction
26
Where do you find merkel cells?
specialized regions such as the lips, oral cavity, and palmar skin
27
What are merkel cells associated with?
a terminal neuronal axon
28
Where will you find eccrine sweat glands?
All over the body, greatest number on the face, chest and back
29
What type of sweat glands are most important in regulating our body temp?
Eccrine glands
30
Which sweat glands can be attributed to body odor?
Apocrine
31
Where will you find apocrine sweat glands?
They are fewer in number, found in axilla, groin, scalp, face, and abdomen
32
What happens when you use a steroid cream on a contact dermatitis?
you will slow down the activity of the langerhaan's cells and also decrease the amount of local lymphocytes in that area, interfering with the whole immune process.
33
What are the 2 major layers of the dermis?
Papillary and Reticular
34
Which dermal layer is closest to the epidermis with loose CT?
Papillary
35
Which dermal layer has dense dermal collagen and is more packed together?
Reticular
36
Components of the Dermis? (12)
1. collagen 2. elastin reticulum 3. gel-like ground substance 4. hair follicles 5. sebaceous glands 6. sweat glands 7. blood vessels 8. nerves 9. lymphatic vessels 10. fibroblasts 11. mast cells 12. macrophages
37
What are the components of the subcutaneous fat layer?
Adipocytes, dermal, subcutaneous collagen (continuous with dermis, anchors dermis down)
38
What will you see with people with lots of subcutaneous fat in regards to the structure?
You will see layer of fat then layers of collagen and then more fat (collage in between fat layers), don't know why this is
39
What are the theories behind why there is collagen separating fat layers in humans?
Your body thinks you are storing up for a period of hibernation or cold, your fat layers are separated by collagen to preserve more heat and contribute to greater thermogenesis.
40
What are the 4 structural units of nails?
1. the proximal nail fold 2. the matrix from which the nail grows 3. the hyponichium (nail bed) 4. nail plate
41
Nail growth, how many mm per day?
1mm or less per day
42
If you removed a pt's toenail, how long should you tell them it will take for their nail to grow back?
around a month
43
Lymphocytes in the skin express what specialized antigen?
Cutaneous lymphocyte associated antigen (CLA)
44
Describe the innate immune response in the skin
Dirt/dust in wound, gets taken up by Langerhaan's cells, macrophage-like cells release cytokines, the cytokines activate other macrophage like cells in the dermal layer (dendritic cells, macrophages), these cells engulf and destroy the dust/dirt particle automatically.
45
Describe adaptive immunity of the skin
Langerhaan's cells process a foreign antigen, present it to helper T cells which recognize it, produce cytokines (IL-2 + others) to recruit more T cells, from here an immune response is mounted.
46
What does DEJ stand for?
Dermal epidermal junction
47
Describe the skin changes that happen with aging
skin becomes thinner, drier, wrinkled, and demonstrates changes in pigmentation, shortening and decrease in number of capillary loops, fewere melanocytes and L cells, atrophy of sebaceous, eccrine, and apocrine glands, changes in hair color (hormonal), fewer hair follicles and growth of thinner hair.
48
What goes with each of these respectively as the "bigger" version? Macule, papule, vesicle
macule < patch, papule < plaque, vesicle < bullae
49
What are people usually referring to when they say they have a blister?
a bulla
50
Chronic dermatitis = ?
Lichenification
51
What is it called when you have separation of the nail plate from the nail bed?
Onycholysis
52
Hyperkeratosis = ?
Thickening of the stratum corneum, a QUALITATIVE abnormality of the keratin
53
What will you sometimes see in people who have had radiation to a section of skin? When was this discovered?
hyperkeratosis, when they used to use radiation to get rid of plantar's warts, 20 years later lots of these people developed hyperkeratosis
54
Parakeratosis = ?
Keratinization with RETAINED NUCLEI of the stratum corneum, the cells are not maturing as they migrate up.
55
Is parakeratosis normal?
Yes on mucuous membranes (mouth, vaginal epithelium)
56
Hypergranulosis = ?
Hyperplasia of stratum granulosum, usually due to constant rubbing
57
Could you use the term acanthosis to describe a lesion?
No, would need path report to know this
58
Acanthosis = ?
Diffuse epidermal hyperplasia, increase # of cells in all layers, very difficult to distinguish from hyperkeratosis, won't be raised.
59
What is acanthosis usually caused by?
Chronic inflamm, irritation
60
Papillomatosis = ?
surface elevation caused by hyperplasia and enlargement of contiguous dermal papilla, this WILL be raised up in small area
61
How can you distinguish papillomatosis from acanthosis?
Acanthosis will not be raised up, papillomatosis will.
62
Acantholysis = ?, example?
Loss of intercellular cohesion between keratinocytes, ex. pemphigus vulgaris
63
How will acantholysis present?
As a papule over a macule
64
Spongiosis = ?
Intracellular edema of the epidermis
65
Hydopic swelling = ? what do you see this with?
(ballooning), intracellular edema of keratinocytes, seen in viral infections
66
Exocytosis = ?
Infiltration of epidermis by inflammatory cells from the dermis
67
How do you distinguish an erosion from an ulceration?
an ulceration will bleed because it goes through to the dermis, an erosion is only part of the epidermis and won't bleed.
68
What is vacuolization?
Formation of vacuoles within or adjacent to cells
69
"lentiginous" refers to ?
Linear pattern of melanocyte proliferation within epidermal basal layer
70
What are the 3 broad issues that contribute to skin pathology?
1. Degeneration 2. Inflammation (dermatoses) 3. Neoplasms
71
What is the most common type of vitiligo?
Non-segmented, found all over the body
72
What are the causes of vitiligo?
autoimmune (Abs destroy melanocytes), genetic component, and oxidative stress, immune system becomes more active during physiological stress
73
What is the hallmark of ephelis?
appear after sun exposure (or increase/become darker)
74
When can you see someone's freckles the most?
If they become anemic
75
What causes freckles (ephelis)?
increased amount of melanin produced within basal keratinocytes, melanocytes may be SLIGHTLY enlarged but NORMAL density.
76
What condition looks like very large freckles?
Lentigo
77
Describe lentigo
benign localized hyperplasia of epidermal melanocytes (linear, non-nested hyperplasia, in this case there IS an increase in number of melanocytes
78
Which age group does lentigo affect?
All ages
79
Can you see lentigo in mucous membranes?
Yes
80
How large are lentigo patches?
small, 5-10 mm diameter
81
How do you distinguish lentigo from freckles?
they do not wax/wane, don't get darker in sunlight
82
Melanocytes should only be in _________ and ___________?
epidermis and surrounding hair follicles
83
What is the difference between Becker's nevus and Cafe au lait spots?
Becker's nevi break up into smaller macules at the periphery, cafe au lait spots do not.
84
What is a becker's nevus?
It is NOT nevocellular, it lacks nevus cells, but it is a developmental anomaly that shows up as a brown macular patch or patch of hair or both.
85
When do you need to get a neuro consult on an infant with cafe au lait spots?
If they have 6 or more, could have neurofibromatosis type 1
86
Describe the lesions assoc. with melasma
Dark, irregular, well-demarcated, hyperpigmented macules to patches
87
Where do you see melasma?
upper cheek, nose, lips, upper lip, and forehead
88
Cause of melasma?
Stimulation of melanocytes or pigment-producting cells by estrogen and progesterone to produce more melanin pigments when exposed to sun
89
Estrogen is a ___________ hormone?
trophic, stimulates other things to be active
90
Melanocyte nevus = ?
A mole!
91
Size of nevi?
2.0mm
92
Nevi can be _______ or ________? Which is more common?
congenital or acquired, acquired is more common
93
What is "nevus" mean?
It denotes any congenital skin lesion, just a type of melanocyte. If use the term "nevus" means the melanocytes are nested together.
94
What do nevus cells NOT have?
dendritic processes, they won't spread out into other layers
95
The earliest melanocyte nevus lesions are?
junctional, pretty flat, more pigmented and closer in association to melanoma
96
Describe the characteristics of junctional nevi
Located along the DEJ, uniform nuclei, with little or no mitotic activity
97
What do most junctional nevi do? What is this process called?
Grow into the underlying dermis, when they are then considered a "compound nevus", this process is called maturation
98
Which nevi are more elevated, junctional or compound/demal?
Compound/dermal are more elevated than junctional
99
What are older nevi called? Why is this?
They are called intradermal, because eventually they have no epidermal nests and are just in the dermis
100
When a stem cell factor binds to a cKIT receptor in the skin, what gets turned on?
RAS
101
What does RAS play a role in?
cell life cycle and proliferation, makes cells live longer and proliferate more.
102
What does p16 do?
Turns OFF cell proliferation
103
What is BRAF?
encodes for serine/threonine kinase, a positive mediator of RAS signals
104
When BRAF is mutated and stimulates increased cell proliferation, what is also stimulated?
p16, which turns the system back "off"
105
Describe the appearance of a compound nevus.
Raised, dome-shaped, symmetry with uniform pigmentation (suggests benign), intraepidermal nevus cell nests with cords of nevus cells in dermis.
106
What happens to a nevus after a long time that patients may confuse with melanoma?
the melanocytes lay down fibrotic tissue, it won't change anymore
107
What is the condition where you have nevi all over your body?
Dysplastic Nevus Syndrome
108
What is the probability of developing melanoma if you have dysplastic nevus syndrome?
>50% by age 60
109
What are the similarities between mongolian spots and nevi of Ota/Ito?
Both are congenital (apparent w/in first year of life), have a "mottled" appearance, and occur more often in asians and AA.
110
What are the differences between mongolian spots and Nevi of Ota/Ito?
Ota: trigeminal nerve, 1st and second divisions, Ito: posterior supraclavicular and lateral brachiocutaneous nerves.
111
Dermal melanocytosis = ?
Mongolian spots, nevus of Ota and Ito
112
In dermal melanocytosis, what occurs?
melanocytes in dermis actively synthesize melanin (this is abnormal).
113
What is the "Tyndall effect"?
scattering of shorter wavelengths by dermal melanin that gives mongolian spots their blue color.
114
What is "variegation"?
Variability in pigmentation, as seen in dysplastic nevi
115
What are the characteristics of dysplastic nevi?
larger than acquired nevi (>5 mm), flat macules, slightly raised plaques, or target-like lesions with darker raised center (pebbly surface), irregular flat periphery, variability in pigmentation, irregular borders, usually compound, occur on BOTH sun-exposed and sun-protected areas.
116
What does "cytologic atypia" mean?
irregularly shaped, dark staining nuclei, seen with dysplastic nevi
117
CDKN2A = ?
P16
118
Dysplastic nevus syndrome is autosomal _____?
Dominant
119
What mutations are associated with Dysplastic Nevi Syndrome?
CDKN2A (p16) or CDK4/6 gene mutations
120
Which pathway would you want to affect with drug therapy in treating dysplastic nevi syndrome?
the cell proliferation pathway (BRAF side)
121
Explain what the CDKN2A mutation would do?
p16 usually gets turned on when BRAF is turned on to stop the cell proliferation from getting out of control, when it is mutated, it can't turn this cell proliferation off (can't turn off CDK 4/6)--->dysplastic nevi
122
Explain what the CDK 4/6 mutation would do?
In this case, p16 can do its job and down regulated CDK 4/6 as it is supposed to but this mutation causes CDK 4/6 to be resistent to this input.
123
Can you screen people who may potentially have the CDK 4/6 or CDKN2A mutations?
Yes, starting to do more of this.
124
Why is it so important to not miss a potential malignant melanoma?
B/c once it has metastasized it is very resistent to treatment
125
What is the only primary skin cancer than can kill you?
Malignant melanoma and RARE merkel cell tumor
126
Prognosis for MM is related to ?
VERTICAL growth (breslow staging)
127
A nevus lesion that is >?? raises concern for MM?
6 mm
128
At presentation, (when people usually come in concerned about a mole), how big are they usually?
> 10 mm
129
ABCDE?
A=Asymmetry B=Borders/Bleeding C=Colors D=Diameter E=Erythema/Evolving?
130
Lentigo maligna?
indolent type, usually on the face, seen in elderly, growing slowly radially, not changing very much
131
Most common type of MM?
Superficial Spreading
132
Acral/mucosal lentiginous MM?
UNrelated to sun exposure, could be anogenital
133
What does the appearance of a nodule within a mole indicated?
correlates with the emergence of a clone of cells w/ metastatic potential.
134
If you are concerned about MM and the lesion feels more nodular, what does this mean?
More chance of metastasis, as the melanoma grows deeper (vertical growth), tend to feel more nodular.
135
Do males or females have a worse prognosis with MM?
males have worse.
136
What are "Clark's Levels"?
A scale for MM 10 year survival rate based on Breslow Depth (1-5), 5 being worst.
137
<____mm in depth = good prognosis for MM?
<1.7 mm depth
138
What percentage of MM are familial?
10-15%, many have dysplastic nevi syndrome
139
What is mutated in 40% of familial melanoma?
CDKN2A (p16)
140
What 3 tumor suppressors does p16 code for?
p15/INK4b, p16/INK4a, p14/ARF
141
What does p16/INK4a normally do?
It normally enhances activity of TSGs of Rb family by inhibiting CDK4.
142
What does p14/ARF normally do?
Enhances activity of p53 by inhibiting activity of MDM2.
143
What are the other gene mutations they have found in fair skinned individuals that may make them more susceptible to MM?
MC1R (melanocortin-1-receptor), ASIP (regulator of melanocortin receptor signaling), TYR (tyrosinase enzyme).
144
BENIGN epidermal tumors are derived from?
keratinizing stratified squamous epithelium of the epidermis and hair follicles, these are NOT due to melanocytes
145
How will benign epidermal tumors have increased pigmentation?
d/t to the accumulation of keratin
146
Appearance of Seborrheic Keratosis?
Round, flat, coin-like, waxy plaques, "stuck-on appearance"
147
What is the surface of seborrheic keratosis like?
velvety to granular
148
What is a keratin filled horn cyst and pseudocyst? What are they assoc. with?
assoc. with seborrheic keratosis, keratin filled pocket at skin surface, if open to surface, called "pseudocyst"
149
What age group gets seborrheic keratosis? What population is it enhanced in?
middle aged or older, enhanced in people of color
150
What is Dermatosis papulosa nigra?
multiple small seborrheic keratosis lesions on the face (Morgan Freeman)
151
What mutation is assoc. with Seborrheic Keratosis?
Mutation in FGFR3 gene (fibroblast growth factor receptor 3)
152
Explain what happens with the FGFR3 mutation.
It is always on, it stimulates cells to continuously produce keratin, drives the growth of the sebrorrheic keratoses.
153
What should you be concerned about if someone with previously clear skin comes in with a huge outbreak of seborrheic keratosis?
Paraneoplastic syndrome--->GI carcinoma releasing growth factors out of control
154
What is the Leser-Trelat sign?
Explosive development of seborrheic keratosis
155
Thickened hyperpigmented skin with velvet-like texture is?
Acanthosis Nigricans
156
What are the 2 types of acanthosis nigricans?
Benign (80%) and Malignant
157
Describe benign acanthosis nigricans
Autosomal dominant with variable penetrance, is assoc. with obesity or endocrine abnormalities (pituitary or pineal tumors and DM), is part of several rare congenital syndromes
158
When does malignant acanthosis nigricans occur? What is associated with?
Occurs quickly in middle aged to older people, is assoc. with underlying cancers (GI adenocarcinomas--->stimulate fibroblasts to lay down more keratin (what causes the hyperpigmentation)
159
When you see numerous, repeated PEAKS and VALLEYS in the epidermis, what should you think of?
Acanthosis Nigricans
160
What other conditions can the familial type of Acanthosis Nigricans be assoc. with?
Achondroplasia (mutation in FGFR3), Thanatophoric dysplasia (mutation in FGFR3)
161
Fibroepithelial polyp = ?
Skin tag, acrochordon, squamous papilloma
162
A soft, flesh-colored, "bag-like" tumor is?
a fibroepithelial polyp (skin tag)
163
What should you think of when you see "fibrovascular cores"?
Fibroepithelial polyp
164
Disorders assoc with fibroepithelial polyps?
Diabetes, Obesity, Intestinal polyposis
165
What happens to fibroepithelial polyps during pregnancy?
They become more numerous or prominent (like melanocyte nevi and hemangiomas)
166
What is a "wen"?
An epidermal (inclusion) cyst
167
What is inside a wen?
keratin and lipid debris
168
Wall: Resembles normal epidermis
Center: Filled with laminated strands of keratin and lipid debris
Epidermal Inclusion cyst
169
Wall: resembles follicular epithelium withOUT granular cell layer
Center: Filled with homogenous mixture of keratin and lipid
Pilar or trichilemmal cyst
170
Wall: Similar to epidermal inclusion with multiple appendages budding outward
Dermoid Cyst
171
Resembling sebaceous gland duct from which numerous compressed sebaceous lobules originate
Steatocystoma simplex
172
What is steatocystoma multiplex?
a missense mutation in keratin, causing keratin to be produced in abnormal amounts
173
Tumors that arise from structures that stick out from epidermis are termed?
Benign adnexal (appendage) tumors
174
Benign adnexal (appendage) tumors are benign but can be confused with?
BCC
175
Some benign adnexal (appendage) tumors have a mendelian inheritance pattern, with mutations in which genes? What will these types be like?
TSG, PTEN; more aggressive if inherited mutation
176
If someone inherits a mutation causing benign adnexal tumors, what will they have a predisposition for?
internal malignancy
177
Benign adnexal tumors can involve?
Hair follicles, sebaceous glands, and sweat glands
178
Apocrine sweat glands secrete their fluid how?
Through membrane bound vesicles
179
General characteristics of benign adnexal tumors?
Flesh colored, solitary or multiple, papules and nodules, some have predisposition for certain body surfaces.
180
When thinking of names of benign adnexal tumors what should you keep in mind?
They are usually named based on location
181
Where will you find eccrine poromas?
On the palms and soles
182
What are the "turbin-type tumors"?
Cylindromas (found on forehead and scalp)
183
Which benign adnexal tumors look like acne vulgaris?
cylindromas
184
What causes cylindromas (physiologically)?
dominantly inherited, inactivation of TSG CYLD
185
What will a cylindroma look like on biopsy?
islands of cells resembling normal epidermal or adnexal, fit together like a jigsaw puzzle
186
What type of adnexal tumors do you get on your T-zone?
Trichoepitheliomas
187
What causes trichoepitheliomas?
Proliferation of basaloid cells that form primitive structures resembling hair follicles
188
Describe syringomas?
benign adnexal tumors of eccrine sweat glands that affect the lower eyelids (multiple small tan papules)
189
Sebaceous adenomas can convert to what on rare occasion?
adenocarcinoma
190
This adnexal tumor can be associated with internal malignancy in Muir Torre syndrome (a subset of hereditary nonpolyposis carcinoma syndrome)?
Sebaceous adenomas
191
These are precursors for SCC?
Actinic Keratosis
192
The number one cause for AK is sun exposure, what are the other things that could cause it?
ionizing radiation, industrial hydrocarbons, arsenicals
193
What is the "hallmark" of AK?
parakeratosis
194
What is Imipuimod?
activates immune system by stimulating toll-like receptors; helps body take care of AK before it becomes SCC
195
What is called when you have keratosis on the lips?
Actinic chelitis
196
What will the basal layer look like with AK?
Atypical, have huge nuclei
197
SCC is the ___ most common tumor from "sun exposure".
2nd, BCC is first
198
What percentage of SCC will metastasize to nodes?
<5%
199
These tumors can cause skin ulceration, have atypical nuclei and infiltrating margins?
SCC
200
SCC in situ = ?
Bowen's Disease; if no invasion through DEJ
201
What levels of epidermis do SCC lesions involve?
ALL of them
202
The pathogenesis of SCC usually involves what mutation?
DNA damage due to UV light which mutates p53, can no longer do its job of killing off atypical cells
203
UV light can cause mutations in p53, what else does it do?
dampens the immune surveillance (LH cells or lymphocytes, lessens their effect)
204
What happens with DNA damage due to the sun, what "senses" this damage?
The DNA damage is sensed by kinases (ATM and ATR) which normally then upregulate p53 to destroy the damaged cells but if p53 is mutated this doesn't work
205
Incidence of SCC is proportional to what?
degree of lifetime sun exposure
206
SCC also has an association with ?
Immunosuppression
207
Which types of HPV are assoc. with SCC?
5 and 8
208
What is the difference between a tumor being "invasive" and having "metastatic potential"?
Invasive refers to spread locally in the area where the lesion originated. Metastasis refers to spreading to other parts of the body.
209
What is a glioblastoma multiforme?
one of the most invasive malignant type of brain tumors, but will never metastasize, stays in brain.
210
What will you see on a path report if the lesion in question is a BCC?
BLUE palisading nests
211
What is an inherited disorder that involves lacking DNA repair?
Xeroderma pigmentosum, kids cannot go out in the sun bc instead of the sun mutating their DNA repair genes, they are born with the mutations
212
What is the most common invasive cancer in humans?
BCC
213
Most common appearance of BCC?
pearly papules with telangiectasis
214
Can BCC contain melanin?
Yes, they can, don't always
215
Advanced BCC lesions can?
ulcerate, become locally invasive
216
How do the tumor cells of BCC look?
They resemble normal basal layer of epidermis but are squished together (palisade)
217
What are the 2 patterns of BCC growth?
Multifocal and Nodular
218
Where do multifocal BCC growths arise from?
Epidermis, extend over several square cm
219
Which BCC lesions start in the follicular epidermis and grow downward into the dermis?
Nodular lesions
220
Nevoid basal cell carcinoma syndrome = ?
Gorlin Syndrome, an autosomal dominant disorder on Chm 9, PTCH gene mutation
221
What syndrome led to finding the genes that cause BCC?
Gorlin Syndrome (Nevoid basal cell carcinoma syndrome)
222
When someone has Gorlin syndrome, they have a mutation where? and what has to occur for them to have a BCC?
They have a PTCH gene mutation on Chm 9, they have one normal allele, so this normal allele must become inactivated by UV light for them to have symptoms.
223
Usually people with Gorlin Syndrome have BCC by age?
before age 20
224
What is Gorlin Syndrome assoc. with?
medulloblastomas and ovarian fibromas
225
What is the normal action of p53?
To turn on apoptosis and to repair a cell that is abnormal (signal DNA repair)
226
What genetic defects do kids with xeroderma pigmentosa have?
Defects in PTCH and p53
227
What does the PTCH gene encode for?
a receptor for Sonic Hedgehog gene
228
Absence of PTCH causes what?
activation of SMO which leads to BCC
229
What happens in normal people when the sonic hedgehog protein binds to PTCH?
It dissociates from SMO so SMO becomes activated and initiates cell proliferation
230
Pts with NON NBCCS have which type of mutations?
30% have PTCH mutations, 40-60% have p53 mutation
231
What tumor can look like small cell cancer of the lung?
Merkel cell carcinoma (very rare)
232
How is angioedema different from urticaria?
It is closely related by characterized by deeper edema of both the dermis and subcutaneous fat
233
What does histamine specifically cause at the capillary level?
causes endothelial cell retraction (causes the endo cells to pull away from each other) increasing vascular permeability.
234
Why is IgG the best Ab?
b/c it is so heavily recognized by our phagocytic cells (neutrophils, macrophages)
235
Define Dermatoses
Inflammatory processes that occur within the skin
236
Why do some people get urticaria?
Some people are just genetically prone to produce more IgE in response to certain stimuli, and there are a TON of receptors on mast cells for IgE---->bind them, release histamine
237
Besides production of IgE in response to a stimulus, how else can mast cells be stimulated to release histamine?
C3A and C5A (part of complement) can activate mast cells and cause them to de granulate
238
What are the two ways to activate complement?
C1----->everything else
| C3------>everything else (this way bypasses C1 and C2)
239
What can the lesions of urticaria look like?
they can vary from small pruritic papules to large edematous plaques
240
What can be an instigator for urticaria?
ASA
241
What is complement mediated urticaria?
hereditary angioneurotic edema (inherited deficiency of C1 inhibitor, causing C1 to constantly be active, constantly degranulating mast cells), in a majority of cases there is no underlying cause. So anytime complement is activated these pts will have urticaria-like lesions/symptoms.
242
If pt has persistent urticaria, what underlying diseases could they potentially have?
collagen vascular disorders, Hodgkin lymphoma
243
Eczema is greek for ?
"to boil over"
244
All forms of eczema are characterized by?
red, papulovesicular, oozing, and crusted lesions
245
If eczema is persistent what can the lesions transform into?
raised, scaling plaques due to acanthosis and hyperkeratosis
246
epidermal ________ is a hallmark of acute eczema
spongiosis
247
What cells play a central role in contact dermatitis?
Langerhaan's cells
