Ch0 Basic Principles Flashcards
1
Q
What is erythema caused by
A
Erythema is caused by vasodilation and/or increased blood flow within the dermis
2
Q
Entities that have the Koebner phenomenon
A
- psoriasis
- vitiligo
- lichen planus
- lichen nitidus
- cutaneous small vessel vasculitis
- Still disease
3
Q
What does Woods lamp emit
A
UVA at 365 nm
4
Q
How does a Woods lamp work
A
- lamp 4-5 inches away from where you are examining
- after the target absorbs the UVA radiation, there is some loss of energy and therefore the emission is at a longer wavelength within the visible range
5
Q
What does vitiligo look like under woods lamp
A
chalk-white to dullish blue - fluorescence of dermal collagen observed due to a marked decrease or absence of melanin within the epidermis
6
Q
Hyperpigmentation under Woods lamp
A
- Epidermal melanin –> enhances brown colour
- Dermal melanin –> difference between lesional and non-lesional skin becomes less obvious
7
Q
Pseudomonas under Woods lamp
A
Green
8
Q
Corynebacterium under Woods lamp
A
Coral red
9
Q
P acnes under woods lamp
A
Orange-red (in comedones)
10
Q
Pit versicolor under Woods lamp
A
Yellowish-white
Yellow-green
Golden
Copper-orange
11
Q
Tinea capitis under Woods lamp due to Microsporun
A
Blue-green to yellow-green
12
Q
Trichophyton schoenleinlii under Woods lamp
A
blue-wehite
13
Q
How long does parakeratosis take to develop (scale)
A
2 weeks
14
Q
How long does tense bullae last for
A
less than a week
15
Q
Causes of a rash and fever
A
- Infectious
- Bacteria: toxic shock, SSSS, scarlet fever, septic emboli, secondary syphilis
- Viruses: exanthems, disseminated zoster
- Fungi
- Protozoa
- Kawasaki
- Inflam:
- Drug reactions - DRESS< AGEP
- EM, SJS
- Primary cutaneous disorders
- Rheum disorders
- GVHD
- Neoplastic: lymphoma
- Inherited
16
Q
Acute cutaneous eruptions in otherwise healthy individuals
A
- urticaria
- acute allergic contact dermatitis, ICD
- Drug eruptions
- Pit rosea
- Viral exanthems
17
Q
Where to biopsy in vasculitides
A
Centre of early lesion
18
Q
Where to biopsy in livedo reticularis
A
centre of pale areas defined by surrounding venous plexus network, corresponds to site of ascending arteriole
19
Q
Where to biopsy CT disease
A
fully developed lesion, not scarred
20
Q
Where to biopsy alopecia
A
Active advancing edge, ares of perifollicular inflammation
21
Q
Where to biopsy infectious
A
Mature lesions, if ulcerated inflammatory border
22
Q
Ulcerative dermatoses where to biopsy
A
Active edge of ulcer or early lesion
23
Q
Where to biopsy pigmentary lesion
A
Get non-lesional skin as well
24
Q
Where to biopsy urticaria
A
Edge of lesion as well
25
Vacuolar definition
Degeneration of basilar keratinocytes with little or no inflammation
26
Lichenoid definition
lymphocytes directly engaged in the destruction of basilar keratinocytes
27
Spongiosis definition
- intercellular oedema, widened spaces between keratinocytes with elongation of intercellular bridges. Often associated with exocytosis of inflammatory cells
- Acute, subacute, chronic
- When chronic - may be more acanthosis (thickening of the epidermis)
28
Psoriasiform definition
Epidermal hyperplasia - elongation of rete ridges
29
Pseudoepitheliomatous hyperplasia definition
related to psoriasiform - irregular, hyperplasia of the epidermis and/or adnexal structures. Can occur from chronic rubbing/scratching, but can be with inflammatory etc
30
Acantholysis definition
- discohesion of keratinocytes due to disruption of desmosomes
- Identifying level of epidermis
31
Ballooning degeneration definition
intracellular oedema in response to cytotoxic events --> presence of abundant pale cytoplasm of keratinocytes in the spinous zone. When ballooning is severe --> keratinocyte rupture --> reticular degeneration and epidermal necrosis
32
Granulomatous vasculitis
histiocytes within and around BV walls with fibrin/degenerative and necrotic changes. Seen in a restricted group of diseases: GPA, EGPA, temporal arteritis
33
Nodular and diffuse dermatitis definition
similar to perivascular dermatitis, but inflammatory infiltrate has enlarged and coalesced to form one or multiple nodules within the dermis
34
4 histopathologic types of granulomas
- Tuberculoid --> epithelioid histiocytes, surrounded by a dense infiltrate of lymphocytes and plasma cells, +/- central caseation. May be Langhan type, associated with cutaneous infections, lupus miliaris
- Sarcoidal --> epithelioid histiocytes with minimal lymphocytic infiltrate - naked tubercles
- Palisaded 'necrobiotic' - epithelioid histiocytes aligned as a rim around a central area of degenerated collagen with different tinctorial qualities. All palisaded granulomas are markedly palisaded, and histiocytes may be distributed interstitially --> interstitial granuloma
- Suppurative --> comprised of neutrophils within and sometimes among or surrounding, aggregates of epithelioid histiocytes
35
Langerhan cell histiocytosis brief histo overview
reniform (kidney bean-shaped) nuceli, positive for S100, CD207 and CD1a
36
Non-LCH brief histo overview
range of cytologic features - vacuolated, spindle shaped, foamy, scalloped, oncocytic. S100-, CD1a- and CD68+ (nonspecific marker of histiocyte lineage)
37
Lipophage definition
Foamy histiocytes filled with lipid
38
Questions to ask when assessing panniculitis
- septal or lobular?
- vasculitis or no?
- type of inflammatory infiltrate?
- cytologic atypia?
- fat necrosis - hyaline changes, basophilic saponification
39
Causes of invisible dermatoses
Stratum corneum:
Superficial infections - tinea versicolor, dermatophytosis, erythrasma, pitted keratolysis
Keratinization: ichthyosis, DSAP
Basilar layer - pigment issues: vitiligo, melasma, CALM
Superficial dermis:
Infestations - onchocerciasis,
Mast cells: TMEP
Endogenous deposition: macular amyloidosis
Superficial and deep:
Exogenous substance: argyria
Endogenous: systemic amyloidosis
Collagen: collagenoma, atrophoderma
Elastic tissue: naevus elasticus, anetoderma
Absence of normal epithelial structure:
hypohidrotic ectodermal dysplasia
40
What to do when deposition of materials within skin
- some materials are limited to the cutaneous adnexa --> silver
- polarized light or darkfield microscopy might be helpful
41
H&E marks what
- basophilic structures (nuclei and granular layer of the epidermis), eosin marks eosinophilic structures - cytoplasm, collagen, muscle, nerve, fibrin
- Elastic tissue does not stain with H&E --> van Gieson
42
Alcian blue
mucinoses, lupus, blue
43
Leder
myeloid and mast cells
44
Colloidal iron
mucinoses, lupus
45
Congo red
amyloid
46
Crystal violet
Acid mucopolysaccharides and amyloid
47
Fontana masson
Melanin, black
48
Giemsa
Nuclei of cells, microorganisms - Leish, histo, mast cell granules
49
Methenamine silver
Fungal cell walls, stains black
50
Gram
Positive- blue
| Negative - red
51
Masson's trichome
Smooth muscle - pink
| Collagen - blue/green
52
Myeloperoxidase
Immature myeloid cells - orange
53
Orcein
- for elastic tissue disorders
- Collagen - pink
- Elastic tissue - dark brown
- Muscle and nerves - yellow
54
PAS stain
glycogen, fungal walls, neutral mucopolysaccharides, fibrin, basement membranes, red --> mycotic infections, DLE, PCY
55
Perls iron
haemosideron and ferric ions - blue
56
Sudan black
lipids, black
57
Sudan orange
Lipids, orange
58
Van Gieson
- Collagen - pink-red
- Elastic - black
- Muscles and nerves - yellow
59
Von kossa
Calcium, black
60
Ziehl-neelson
Acid fast bacteria, red
61
What is immunohistochemistry
use of immunologic tehcniques to identify cellular antigens that are not visible
- antibody is conjugated to an enzyme that can catalyze a colour producing reaction when the antibody-enzyme conjugate is bound to the appropraite antigen within tissue - enzyme is often peroxidase
62
Diagnosis of tumours with sebaceous differentiation
Adipophilin
63
Distinguishes BCC from trichoepithelioma
Bcl2
64
Distrinction of BCC from other cutaneous basaloid tumours
Ber-EP4
65
Tubular differentiation in epithelial tumours, diagnosis of benign and malignant adnexal neoplasms
CEA
66
Low molecular weight cytokeratin, in simple epithelia and Merkel cells
Specific for Merkel cell carcinoma
Cutaneous mets from different types of adenocarcinomas
CK20
67
Ductal differentiation in eccrine and apocrine tumours
| Positive in most sebaceous glands
EMA
68
Breast carcinoma metastases
| Sweat gland carcinoma with apocrine differentiation
Gross cystic disease fluid protein 15
69
Myoepithelial neoplasms
| Distinction of primary cutaneous adenocarcinoma (positive) versus cutaneous mets from visceral adenocarcinomas
p63
70
Screening tumours for epithelial origin
| Useful for SCCs
Pancytokeratin AE1/AE3
71
S100
Family of low molecular weight calcium binding proteins
Neural crest-derived cells
Use for: melanocytic naevi and melanoma, most sensitive marker for spindle cell/desmoplastic melanoma
Alsot stains malignant peripheral nerve sheath tumours and clear cell sarcoma
72
Melan-A
Melanocytic naevi and melanomas
73
HMB45
Melanocytic naevi and melanomas
Diminished straining with dermal descent more frequent in benign tumours
Also may stain melanosome-containing keratinocytes
74
MITF
Nucleus of melanocytic naevus and melanoma cells
Positive staining in almost all melanoma subtypes (80-100%
Helps distinguish solar lentigo from lentigo maligna
Less specificity as can also stain non-melanocytic spindle cell tumours
75
Tyrosinase
Enzyme involved in the initial steps of melanin and biosynthesis, expressed in melanocytes
High sensitivity and specificity
Sensitivity decreases with increased clinical stage
Not helpful in desmoplastic melanomas as only 6% positive
76
SOX10
Highly sensitive for primary and metastatic melanomas
Expressed in all melanoma subtypes
Positive in clear cell sarcomas and peripheral nerve sheath tumours
Useful for detection of micromets in LN
77
BRAF V600E
BRAF - serine/threonine protein kinase in the MAPK pathway
V600E - detected in ~ 50% of cutaneous melanomas
Detection of this leads to treatment with BRAF inhibitors
Also present in LCH
78
P75
Helps to diagnose desmoplastic and neurotropic melanoma with S100 staining is weak or absent
79
PNL2
Melanocytic anevi and melanomas
Not so positive in desmoplastic melanomas
Can be positive in clear cell sarcomas, PEComas and melanocytic schqannomas
80
pHH3
Precise identification of mitoses within tumours
81
Merkel cell carcinoma stains
Chromogranin
CK20
Neurofilament
Snyaptophysin
82
CD31
Benign and malignant vascular neoplasms
| Hsitiocytes also stain positively
83
CD34
Benign and malignant vascular neoplasms
DFSP
Many cutaneous spindle cell neoplasms so poorly specific
84
Bcl-2
Primary cutaneous diffuse large B-cell lymphoma
Distinguishes systemic/nodal follicular lymphomas with secondary skin involvement from primary cutaneous follicle centre lymphomas (negative)
85
Bcl-6
Primary cutaneous follicle centre lymphoma
Reactive lymphoid follicles
T follicular helper cells
86
Dermal and congenital naevi vessels
Comma vessels
87
Melanoma and Spitz Naevi vessels
Dotted vessels
88
Melanoma vessels
Linear irregular vessels
89
What does hairpin vessels mean
keratinizing tumours, seb K and SCC
90
Sebaceous hyperplasia vessels
Crown vessels
91
sBCC vessels on dermoscopy
multiple blood crusts over a red background
92
Red lacunas
Haemangioma
93
Pyogenic granuloma dermoscopy vessels
Red homogenous areas intersected by whitish lines
94
Features of seb k on dermoscopy
- Light-brown fingerprint like structures
- Cerebriform pattern
- Comedo lie openings
- Multiple milia-like cysts
95
BCC dermoscopy features
- Arborizing vessels
- Leaf-like structures
- Large blue-gray ovoid nests
- Multiple blue-gray globules
- Spoke wheel areas
- Ulcerations
96
Types of patterns of melanocytic lesions
- Reticular
- Globular
- Cobblestone - intradermal melanocytic
- Homogenous
- Starburst - Spitz/Reed
- Parallel - acral
97
Acral naevi patterns
- Parallel-furrow pattern
- Lattice-like
- Fibrillar
- Parallel ridge pattern
98
Menzies diagnostic criteria for melanoma
- for a lesion to be diagnosed, must have neither or both negative features, and one or more of the nine positive features
- Negative:
- 1. Symmetry of pattern
- 2. Presence of a single colour
- Positive
- 1. Blue-white veil
- 2. Multiple brown dots
- 3. pseudopods
- Radial streaming
- Scar-like depigmentation
- Peripheral black dots/globules
- Multiple - 5-6 colours
- Multiple blue/grey dots
- Broadened network
