Pathology of Skin Flashcards
1
Q
What is the peidermis mainly made up of
A
Maturing squamous cells
2
Q
Where are melanocytes found
A
At the dermo-epidermal junction and in the basal layer
3
Q
What is the ratio of melanocytes to basal cells
A
1:10
4
Q
What is the granular layer rich in
A
Keratohyalin granules
5
Q
What is the corneal layer made up of
A
Differentiated keratinised cells
6
Q
What happens to corneocytes
A
They are shed from the surface and cause house dust
7
Q
How is pigment shown
A
Melanocytes transfer pigment to keratinocytes via dendritic processes
8
Q
Where are the Langerhan cells located
A
In the upper and mid-epidermis
9
Q
Why are Langerhans cells important
A
In initiating inflammation
10
Q
What is the difference in melanocytes in a pale skinned person compared to a darker skinned person
A
They have the same number of melanocytes but darker skinned people make more melanin
11
Q
The matrix of the dermis is made up of what
A
Type 1 and type 3 collagen
12
Q
What colour is a) collagen when and b) elastin when stained
A
Collagen is pink and elastin is blue
13
Q
What is the ground substance of the dermis made up of
A
Hyaluronic acid and chondriotin sulphate
14
Q
Describe the appearance and location of the papillary dermis
A
Thin and lies just beneath the epidermis
15
Q
Describe the appearance and location of the reticular dermis
A
Thicker than the papillary dermis and contains type 1 collagen
16
Q
What does the reticular dermis contain
A
Appendage structures - sweat glands, pilosebaceous units
17
Q
What is the epidermal Basment Membrane made of
A
laminin and collagen IV
18
Q
What type of cells appear to have halos around them
A
Melanocytes
19
Q
What is parakeratosis
A
Persistence of nuclei in the keratin layer - the skin turnover is too high
20
Q
Define papillomatosis
A
irregular epithelial thickening
21
Q
Give an example of papillomatosis
A
Acanthiosis nigricans
22
Q
What are the 4 main reaction patterns of inflammatory skin diseases
A
Spongiotic-intraepidermal oedema (eczema)
Psoriasiform-elongation of the rete ridges (psoriasis)
Lichenoid-basal layer damage (pemphigoid, pemphigus and dermatitis herpetiformis)
23
Q
What are Munro micro abscess
A
A collection of neutrophils and classsically psoriasis
24
Q
Where are 3 common sites of acne
A
Face
Upper back
Anterior chest
25
What are open comedones
Blackhead since it is oxidised
26
What causes a yellow head
A build up of Sebum and keratine cloggasge
27
Describe the aetiology of acne
Increased androgens at puberty, increased angrogen sensitivity of sebaceious glands
keratin plugging of pilosebaceious units
infection with anaerobic bacterium corynebacterium acnes
28
Rosacea is more common in females than males. true or false
True
29
What are some common features of rosacea
Recurrent facial flushing
Visible blood vessels
Pustules
Thickening of skin - rhinophyma
30
What are some triggers of rosacea
Sunlight
Alcohol
Spicy foods
Stress
31
What are sometimes found in the hair follicles under the microscope in patients with rosacea
Demodex mite in the sebaceious glands
32
What 2 things occur as a secondary phenomenon in many skin disease
eczema
herpes virus infection
burns
33
what type of disease have blisters as the primary feature
Immunobullous diseases
34
What are 3 examples of immunobullous diseases
Pemphigus
Bullous pemphigoid
Dermatitis Herpetiformis
35
What histologically happens in pemphigus
Loss of integrity of epidermal cell adhesion
36
What is the general treatment for pemphigus
Steroids
37
Who is usually affected by pemphigus
Middle aged men or women
38
In simple terms, describe pemphigus
Rare autoimmune bullous disease which is a problem involving cell to cell adhesion
39
What is the end result in pemphigus vulgaris
Acantholysis
40
What forms on the cell surface of pemphigus vulgaris
Immune complexes
41
What is the role of desmoglein 3 in pemphigus vulgaris
It maintains desmosomal attachments
42
What does Pemphigus Vulgaris produce
Fluid filled blisters which rupture to form shallow erosions
43
What areas of the body are affected by Pemphigus Vulgaris
```
Scalp
Face
Axillae
groin
Trunk
```
44
What process is common to all variants of pemphigus ?
Acantholysis (lysis of intercellular adhesion sites)
45
What is bullous pemphigoid
Subepidermal blister
46
What do the IgG antibodies do in Bullous pemphigoid
They react with a major and/or minor antigen of the hemidesmosomes anchoring basal cells to the basement membrane.
47
if you think a patient has presented with bullous pemphigoid, what should be done about it
Punch biopsy or elliptical incisional
48
What type of disease is dermatitis herpetiformis
A relatively rare condition that is autoimmune bullous disease
49
What areas of the body are affected by dermatitis herpetiformis
Elbows, knees and buttocks
50
What does dermatitis herpatiformis have a strong association with
Ceoliac disease
51
What haplotype is dermatitis herpetiformis
HLA-DQ2
52
What is the presenting complaint of dermatitis herpetiformis
Intensely itchy lesions-symmetrical
53
What is the hallmark of dermatitis herpetiformis
Papillary dermal microabscesses
54
What do IgA antibodies target in dermatitis herpetiformis
Gliadin component of ggluten but cross react with connective tissue matrix proteins
55
Immune complexes form in dermal papillae and do what?
Activate complement and generate neutrophil chemotaxins
56
What components of the skin give rise to tumours
All of them
57
Where are melanocytes derived from
Neural crest
58
Early in embryogenesis what mirgrates from the neural crest to what 3 places
Melanoblasts to the:
skin
Uveal tract (of the eye)
Leptomeninges (coverings in the prain)
59
once the melanoblasts have migrated and settled in the skin, what do they form
melanocytes
60
How is pigment transfered
via dendritic processes of the melanocytes
61
What gene is the determinant of what your pigmentation is like?
MC1R (Melanocortin 1 receptor)
62
What does one defective copy of MC1R cause
Freckling
63
What does two defective copies of the MC1R gene cause
Red hair and freckles
64
What does MC1R do?
turn phaeomelanin into eumelanin
65
What is the medical term for freckles
Ephilides
66
What are epihilides
Patchy increase in melanin pigmentation
67
What are Actinic lentigines?
Age or liver spots related to UV exposure
68
Where are you likely to see Actinic lentigines
Face, forearms and dorsal hands
69
In Actinic lentigines, What is there an increase in
Melanin and basal melanocytes
70
Melanoocytic naevi may be 1 of two types. What are these
Congenital or acquired
71
Why is a patient with melanocytic naevi at increased risk of developing melanoma
Based on the fact that they have so many increased melanocytes
72
What allows the formation of simple naevi
During infancy the melanocytes: keratinocyte ratio breaks down at a number of cutaneous sites
73
There are 3 types of naevi. What are these and where are the melanocytes
Junctional: clusters of cells at the DEJ
Compound: Junctional clusters and groups of cells in the dermis
Intradermal: entirely dermal
74
What are the majority of naevi
Compound
75
Describe a typical dysplastic naevi
Generally >6mm
Variegated pigment
Border asymmetry
76
What is a sporadic dysplastic naevi
Not inherited
One to several atypical naevi
risk of MM slightly raised
77
What is a familial dyplastic naevi
strong FH of melanoma
Autosomal inheritance
Lifetime risk of melanoma up to 100%
78
What are the 2 subdivisions of rarer naevi
Halo naevi and blue naevi
79
Describe halo naevi
They have a peripheral halo of depigmentation and show inflammatory regression and are overrun by lymphocytes
80
Describe blue naevi
Entirely dermal and consist of pigment rich dendritic spindle cells - the cellular variant may have mitoses and mimic melanoma
81
Most Spitz naevus are malignant. True or False
False - most are entirely benign
82
What do Spitz naevi consist of?
Large spindle and or epitheliod cells
83
The incidence of melanoma peak at what age
Middle age
84
What are 6 red flag signs that make you suspect melanoma
```
Change in shape
New pigmented lesion that develops in adulthood
Irregular pigmentation
Ulceration
Bleeding
Development of satellite nodules
```
85
What are the 4 main types of malignant melanoma
Superficial spreading
Acral/ mucosal
Lentigo maligna
Nodular
86
What is the most common type of melanoma and where do they appear
Superficial spreading - commonest on the trunk and limbs
87
What type of melanoma are common in sun bed users
Lentigo maligna melanoma
88
What is Vertical Growth Phase
When the melanoma cells invade the dermis forming an expansile mass with mitoses
89
Why is VGP important
Only tumours in the VGP can spread and kill
90
What is different about nodular melanoma compared to the others
It has metastatic potential from the beginning and therefore is considered more aggressive
91
What does melanoma prognosis largely relate to
Breslow depth and ulceration
| Breslow= deepest tumour from granular layer mm
92
What does the suffix a/b mean when staging melanomas
```
a = no ulceration
b = ulceration
```
93
Where are common sites of metastatic spread
```
Skin/ soft tissue
Heart
Lungs
GI tract
Liver
Brain
```
94
What is the treatment for melanoma
Primary excision to give clear margins
| sentinal node biopsy - if positive, regional lymphadenopathy
95
What is used for the treatment for advanced melanoma
Chemo
Immunotherapy
Genetic therapies
96
What is BRAF
an oncogene which drives cell proliferation
97
What are 3 types of precancerous dysplasias
Bowen's disease
actinic keratosis
Viral lesions
98
What is seborrhoeic keratosis?
Benign proliferation of epidermal keratinocytes
99
Where are common places to find seborrhoeic keratosis
Face and the trunk
100
Describe the appearance of seborrhoeic keratosis
stuck on appearance - greasy hyperkeratotic surface
101
What are the 3 main subtypes for BCCs
Nodular
Superficial
Infiltrative
102
Where do basal cells arise from
Epidermis
103
Histologically, superficial basal cell carcinomas often have what appearance
Picket Fence appearance
104
Where does Bowen's disease present
On the legs
105
Where does Actinic keratosis present
On the head and neck
106
Where do viral lesions present
Anogenital skin
107
Histologically what do precursors of squamous cell carcinoma show
Dysplasia
108
Describe Bowen's disease
mostly affects females on their lower legs
Scaly pathc / plaque
Irregular border
No dermal invasion
109
Describe the appearance of Actinic keratosis
Lots of wrinkles and scales, discrete plaques with crusty scale
110
What virus are Viral precursors often associated with
HPV
111
What type of HPV is associated with dysplasia
Type 16
112
What is the behaviour of squamous carcinoma
Generally good prognosis
Locally invasive
Low but definite risk of metastasis
113
What is the appearance of an angiosarcoma
Bluish purple often like a bruise and may bleed
114
Merkel cell carcinoma almost never malignant . True or False
False they are very malignant
115
What are Merkel cells
Pressure receptor cells in the skin
