SKIN 1 Flashcards
1
Q
functions of the skin
A
● Sensation ● Heat regulation by sweating ● Absorption ● Protection ● Excretion of some by products or sweat ● Secretion (SHAPES)
2
Q
LAYER OF THE EPIDERMIS
A
● Stratum corneum ● Stratum lucidum ● Stratum granulosum ● Stratum spinosum ● Stratum basale
3
Q
○ cornified layer
○ contains the keratin
A
Stratum corneum
4
Q
○ firmly adherent to the basement membrane
A
Stratum basale
5
Q
LAYERS OF THE DERMIS
A
● Papillary dermis
● Reticular dermis
6
Q
○ layer where capillaries are located
A
Reticular dermis
7
Q
Mostly fat, but there are also blood vessels and
lymphatics in this layer
A
SUBCUTANEOUS LAYER
8
Q
○ Makes up most of the skin layer
○ “Glued” tightly together by cell junctions known as desmosomes and produce
abundant amounts of keratin protein
A
Squamous epithelial cells (keratinocytes)
9
Q
Squamous epithelial cells secrete soluble molecules that regulate and augment immune response:
A
■ Cytokines
■ Defensins
10
Q
○ Brown pigment that absorbs and protects against potentially injurious UV radiation in sunlight
A
Melanocytes
11
Q
○ Secrete factors that augment innate immune responses, and migrate from skin to regional lymph nodes where they present their antigenic cargoes to T
lymphocytes, stimulating the adaptive immune system
A
● Dendritic cells
12
Q
_______ produced by these T cells mediate the microscopic patterns and
clinical expressions of cutaneous inflammatory and infectious diseases
A
Cytokines
13
Q
Merkel cell is located in the __________
A
epithelial basal layer
may have neuroendocrine or mechanoreceptor functions
14
Q
○ Regulate the adnexal components
○ Influence the function of the innate and adaptive immune cells in the dermis
A
Autonomic Efferent Nerve Fibers
15
Q
Adnexal structures:
A
sweat glands, sebaceous
glands, hair follicles
16
Q
guard against deleterious
variations in body temperature
A
sweat glands
17
Q
have protected niches
harboring epithelial stem cells capable of regenerating superficial epithelial skin structures
A
Hair follicles
18
Q
Traumatic lesion breaking the epidermis and
causing a linear area (e.g., deep scratch), often
self-induced
A
EXCORIATION
19
Q
● Thickened rough skin (similar to a lichen on a
rock)
● Usually, the result of repeated rubbing
A
LICHENIFICATION
20
Q
T or F
LICHENIFICATION is yypically seen in eczematous dermatitis
A
T
21
Q
circumscribed, flat lesions distinguished from surrounding skin by color.
A
MACULA, PATCH
22
Q
Macule: _mm in diameter
A
= 5
23
Q
Patch: _mm in diameter
A
> 5
24
Q
● Separation of nail plate from nail bed
● Can be traumatic or secondary to a fungal
infection
● Common in fungal infections of the nails (tinea
unguium)
A
ONYCHOLYSIS
25
Elevated dome-shaped of flat-topped lesion
PAPULE, NODULE
26
Papule: __mm across
= 5
27
Nodule: __mm across
>5
28
● Elevated, flat-topped lesion, usually >5 mm
| ● Psoriasis
PLAQUE
29
●Dry, horny, plate-like excrescences.
● Typically, dry
● Eczema
SCALE
30
● Fluid-filled raised lesions
VESICLE, BULLA, BLISTER
31
Vesicle size
= 5mm
32
Bullae size
>5mm
33
-Thickening of the stratum corneum
-Usually seen in cases where there is constant
friction of the skin e.g., like a callous
Hyperkeratosis
34
If the hyperkeratotic area shows some nucleus, it
| is called
parakeratosis
35
● Diffuse epidermal hyperplasia
| ● Thickening of the epidermis
Acanthosis
○ normal: 8-10 layers thick
○ acanthosis: more than 8-10
36
Abnormal, premature keratinization within cells
| below the stratum granulosum
DYSKERATOSIS
37
breakdown of epidermis, so there will be a space in between the keratinocytes
Acantholysis
38
● Infiltration of the epidermis by inflammatory cells
| ● Normally the epidermis will show only lymphocytes not PMNs
EXOCYTOSIS
39
● Intracellular edema within the epidermis
| ● Like your cellular swelling, the keratinocytes can undergo spongiosis or swelling of keratinocytes
HYDROPIC SWELLING (BALLOONING)
40
Linear pattern of melanocyte proliferation within the epidermal basal cell layer
LENTIGINOUS
41
● Surface elevation caused by hyperplasia and
| enlargement of contiguous dermal papillae
PAPILLOMATOSIS (Sing. PAPILLOMA)
-can be outward or downward
42
Keratinization with retained nuclei in the stratum
corneum. On mucous membranes parakeratosis
is normal
PARAKERATOSIS
43
Most common pigmented lesions of childhood in
lightly pigmented individuals common among
European, Caucasians, not so much in Filipinos
FRECKLE (EPHELIS)
44
Can be seen in neurofibromatosis type 1
which is similar to freckles histologically, but differ in that they are larger, arise
independently of sun exposure, and
contain aggregated melanosomes
Cafe-au-lait spots
45
freckles morphology
small, tan-red or light brown macules (after sun exposure)
46
Hyperpigmentation of freckles results from
increased amount of melanin pigment within
| basal keratinocytes
47
● Benign localized hyperplasia of melanocytes
● May involve mucous membranes
● Linear (non-nested) melanocytic hyperplasia
restricted to the cell layer immediately above the
basement membrane that produces hyperpigmented basal cell layer.
LENTIGO
48
T or F
Lentigo do not darken when exposed to sunlight
T
49
Melanocytis nevus is a benign neoplasms caused by acquires mutations in components of the _________
RAS signaling pathway
50
-Tan to brown, uniformly pigmented, usually less
than 6mm
-Proliferation of melanocytes in the dermis.
```
MELANOCYTIC NEVUS (PIGMENTED NEVUS,
MOLE)
```
51
If it activates RAS, why do nevi only rarely give
| rise to melanomas?
oncogene-induced senescence.
52
Expression of either activated RAS or BRAF in
normal human melanocytes causes only a limited
period of proliferation that is followed by a permanent growth arrest mediated by the accumulation of
p16/INK4a
53
● When cells of nevi show abnormality like nuclear
enlargement, hyperchromasia
● May be the direct precursors of melanoma
(malignancy of melanocytes)
DYSPLASTIC NEVI
54
Flat macules with a “pebbly” surface or target-like lesions with a darker raised center and
irregular flat periphery
DYSPLASTIC NEVI
55
● Irregularly shaped, dark-staining nuclei
| ● The dermis underlying the atypical cells characteristically shows linear, or lamellar fibrosis.
Cytologic atypia
56
Pathogenesis of dysplastic nevi
-loss of function mutations in CDKN2A
-RAS or BRAF
activation and increased CDK4 activity
-germline mutations that increase the expression of
TERT (gene that encodes the catalytic subunit of telomerase)
57
POTENTIAL STEPS OF TUMOR PROGRESSION IN
| DYSPLASTIC NEVI:
A. Lentiginous melanocytic hyperplasia
B. Lentiginous junctional nevus
C. Lentiginous compound nevus with abnormal
architectural and cytologic features (dysplastic
nevus)
D. Early melanoma (radial growth phase).
E. Advanced melanoma (vertical growth phase)
58
● Most deadly of all skin cancers because they
grow very fast and metastasize very fast
● Strongly linked to acquired mutations caused by exposure to UV radiation in sunlight
melanoma
59
melanoma other sites:
oropharynx, GIT, GUT,
| esophagus, meninges, uvea of the eye
60
In melanoma, About 10-15% are inherited as
autosomal
| dominant trait with variable penetrance
61
Melanoma: single predisposing environmental factor
ULTRAVIOLET RADIATION from sun exposure.
62
Mutations involved in melanoma
● Mutations that disrupt cell cycle control genes (loss of p16/INK4a)
● Mutations that activate pro-growth signalling
pathways.
○ Aberrant increase in RAS and P13K/AKT signalling- promotes cell growth
○ Activating mutations in BRAF are seen in 40-50% of melanomas.
○ Loss of PTEN tumor suppressor leading to heightened activation of
P13K/AKT pathway
● Mutations that activate telomerase.
63
● Striking variations in color.
● Shades of black, brown, red, dark blue and gray.
● Borders are irregular and often notched
Melanoma
64
```
○ Larger than normal melanocytes
○ Large nuclei with irregular contour
○ Clumped chromatin at the periphery of
nuclear membrane
○ Prominent red (eosinophilic) nucleoli
```
Melanoma cells
65
e tumor cells that do not
| produce melanin
Amelanotic melanoma.
66
● horizontal spread of melanomas within the
epidermis and superficial dermis
● At this stage metastasis to other sites seem
remote
RADIAL GROWTH PHASE
67
indolent lesion on the face of older men
Melanoma cells are just in the basal layer. We
can still cure this with surgery.
LENTIGO MALIGNA
68
most common type, usually in sun-exposed skin.
melanoma cells are
already spreading at the epidermis,
SUPERFICIAL SPREADING
69
unrelated to sun exposure.
ACRAL/MUCOSAL LENTIGINOUS
70
● Tumor cells invade downward into the deeper dermal layers as an expansile mass
VERTICAL GROWTH PHASE
71
● Often heralded by the appearance of a nodule
| ● Has a metastatic potential
VERTICAL GROWTH PHASE
72
distance of deepest
tumor cells from the superficial epidermal
granular cell layer
BRESLOW THICKNESS
73
Which is more problematic: radial growth or
| vertical growth?
VERTICAL GROWTH
74
PROGNOSTIC FACTORS
```
● Tumor depth (most important) that implies
vertical growth phase
● Number of mitoses
● Evidence of tumor regression
● Ulceration of overlying skin
● Presence and number of tumor infiltrating
lymphocytes
● Gender
● Location
```
75
WARNING SIGNS OF MELANOMA
```
● Asymmetry
● Borders – irregular
● Color – variegated
● Diameter – increasing
● Evolution or change in appearance
```
76
T or F
| Melanomas are usually asymptomatic
T
77
T or F
Metastatic melanoma is resistant to conventional
chemotherapy and radiotherapy
T
78
Benign epithelial tumors are derived from
○ Keratinizing stratified squamous epithelium
○ Hair follicles
○ Ductular epithelium of cutaneous glands
79
Can be a warning sign of visceral malignancies:
○ Multiple trichilemmomas in Cowden syndrome
○ Multiple sebaceous in Muir-Torre syndrome
○ Multiple seborrheic keratosis in GIT malignancies.
80
● Common epidermal tumors
● Middle aged or older individuals
● Arise spontaneously and particularly numerous
on the trunk
SEBORRHEIC KERATOSES
81
Seborrheic keratosis:
In darker complexioned people, multiple lesions on the face are termed
dermatosis papulosa nigra
82
sudden eruption of multiple seborrheic keratoses in the
skin, the skin is okay and then suddenly there you
see plenty of several seborrheic keratoses
Sign of Leser – Trelat
83
- Round, flat, coin-like, waxy plaques
| - Several keratin-filled cyst
SEBORRHEIC KERATOSES
84
-Thickened hyperpigmented skin with a “velvet-like” texture
-In flexural areas (axillae, skin folds of the neck,
groin and anogenital regions)
ACANTHOSIS NIGRICANS
85
T or F
In Acanthosis nigricans, 20% of cases are associated with cancers (GIT adenocarcinomas)
T
86
Acanthosis nigricans is associated with germline mutations in the receptor __________
tyrosine kinase (FGFR3)
87
typical signs of seborrheic keratosis.
Acanthosis, hyperkeratosis and presence of horn cysts at epidermis containing keratin
88
commonly called skin tag
FIBROEPITHELIAL POLYPS
89
T or F
| Majority of fibroepithelial polyps is sporadic
T
90
Soft, flesh-colored, bag-like tumors often attached to
| the skin by a slender stalk
FIBROEPITHELIAL POLYPS
91
Histologic feature of fibroepithelial polyps
fibrovascular cores covered by benign
| squamous epithelium
92
ADNEXAL TUMORS
```
Eccrine poroma
Cylindroma
Syringomas
Sebaceous adenomas
Pilomatricomas
```
93
● Predominantly on palms and soles where sweat
glands are numerous
● Dermal proliferation of your sweat glands
ECCRINE POROMA
94
● ductal differentiation
○ Usually on forehead and scalp
○ “turban tumor” because it can grow and replace skin
CYLINDROMA
| pieces of jigsaw puzzle
95
● Eccrine differentiation
| ○ Multiple, small tan papules in lower eyelids
SYRINGOMAS
| irregular nest of cells
96
What is more common, sebaceous adenoma or carcinoma?
Adenoma
97
Sebaceous adenoma can be associated with what syndrome
Muir – Torre syndrome
98
● Follicular differentiation
| ● Also called calcifying epithelioma of Malherbe
PILOMATRICOMAS
99
Pilomatricomas distinct characteristics:
Ghost cells/Shadow
| cells
100
PREMALIGNANT AND MALIGNANT EPIDERMAL
| TUMORS
Actinic keratosis
Squamous cell carcinoma
Basal cell carcinoma
101
- A premalignant condition in sun-damage skin,
usually of lightly pigmented individuals.
-Exposure to ionizing radiation, industrial
hydrocarbons and arsenicals
ACTINIC KERATOSIS
102
● Rough sandpaper like consistency
Actinic keratosis
103
- lesions on the lips showing so much keratin
actinic cheilitis
104
ACTINIC KERATOSIS:
topical administration of ________, a drug that
activates Toll-like receptors (TLRs), eradicates
up to 50% of lesions, a rate considerably higher
than the spontaneous regression rate of
approximately 5%
imiquimod
105
● Second most common tumor arising on sun-exposed area
-Generally deep invasive and involve the subcutis
SQUAMOUS CELL CARCINOMA
○ The most common is basal cell carcinoma.
○ The most malignant is malignant melanoma
106
T or F
In Squamous cell carcinoma, Tumor incidence is proportional to the degree of lifetime sun exposure
T
107
HPV subtypes involved in squamous cell carcinoma
5 and 8.
108
● Locally aggressive, slow growing, rarely
metastasizing
● Associated with mutations that activate the
Hedgehog pathway signalling
BASAL CELL CARCINOMA
109
Usually present as pearly papules containing
| prominent dilated subepidermal blood vessels.
BASAL CELL CARCINOMA
110
TUMORS OF THE DERMIS
BENIGN FIBROUS HISTIOCYTOMA
DERMATOFIBROMA PROTUBERANS
111
```
● Also called dermatofibroma
○ It is made up of fibrous tissue with presence of histiocytes.
● Legs of young and middle-aged women
● Indolent behaviour
● With numerous histologic variants
```
BENIGN FIBROUS HISTIOCYTOMA
112
BENIGN FIBROUS HISTIOCYTOMA is characterized by
downward elongation of hyperpigmented rete
| ridges (pseudoepitheliomatous hyperplasia)
113
● Well-differentiated fibrosarcoma
● Slow growing, locally aggressive, rarely
metastasize
● Protuberant nodule, often on the trunk
DERMATOFIBROMA PROTUBERANS
114
pattern in dermatofibroma protuberans (micro)
Storiform (cogwheels)
115
The molecular hallmark of dermatofibrosarcoma
protuberans is a translocation involving the genes
encoding ___________
collagen 1A1 (COL1A1) and platelet-derived growth factor-β (PDGFB)
116
TUMORS OF CELLULAR MIGRANTS TO THE SKIN
MYCOSIS FUNGOIDES
| MASTOCYTOSIS
117
MYCOSIS FUNGOIDES originates from the _________
T helper cells CD4+
118
Histologic hallmark of mycosis fungoides
presence of Sezary-Lutner cells
119
● Increased number of mast cells in the skin
MASTOCYTOSIS
120
In mastocytosis, most of the symptoms/signs are due to the effects of
histamine, heparin and other substances from
| the mast cells
121
presents as a pink to tan-brown nodule that may be pruritic or show blister
formation.
Solitary mastocytoma
122
Many cases of mastocytosis have acquired activating point mutations in the ____
-KIT
less frequently, the PDGFR-α receptor tyrosine
kinases.
123
DISORDERS OF EPIDERMAL MATURATION
ICHTHYOSIS
124
● Chronic excessive keratin build-up producing
| fish-like scales
ICHTHYOSIS
125
● Clinical types of Ichthyosis
o Ichthyosis vulgaris
o Congenital ichthyosis erythroderma
o Lamellar ichthyosis
o X-linked ichthyosis
126
Primary abnormality in ichthyosis
defective desquamation, leading to retention of abnormally formed scales
127
caused by a deficiency of
| steroid sulfatase
X-linked ichthyosis
128
QUEN IS PRETTY
YES
