Introduction Flashcards
Sensitivity of naked-eye examination for melanoma detection (dermatologists)
65-80%
Overall benefit of dermoscopy in melanoma Dx
Dermoscopy improves diagnostic accuracy by 10–27%
Advantages of dermoscopy
- significantly improves the in vivo diagnostic accuracy of melanoma
- can differentiate most lesions of the skin from melanoma
- reduces unneeded biopsies
- Basic instrumentation is affordable
- easy to use
- noninvasive technique that allows microscopic visualization of subsurface skin structures not visible to the naked eye
Which are the qualities of a good test?
- Accuracy
- No adverse effects
- target disorder dangerous if left untreated
- effective treatment if diagnosed early
How Can Dermoscopy Help?
Primary difference of dermoscopy vs naked-eye skin examination
- visualize structures below the level of the stratum corneum to the depth of the superficial dermis
Why can’t we observe with naked-eye the morphological structures that are located below the stratum corneum?
- Because the refractive index of the stratum corneum is higher than that of air, much of the incident light is reflected off the surface of the skin
- this diffuse backscattered light overwhelms the retina, and thereby obscures the visualizing of light that is reflected from the deeper layers of the skin
Rationale in using liquid interface in non-polarized dermoscopy(NPD)
- Because there is a closer match of refractive indices within the skin–liquid–glass inter- face, light reflection is decreased, thereby minimizing glare, which in turn makes the stratum corneum appear more translucent
- This optical setup per- mits the observer to see deeper structures in the skin
Best immersion liquid for dermoscopy?
70% alcohol
- it yielded fewer air bubbles & provided clearer images
- reduces bacterial contamination
Best immersion liquid for nail dermoscopy & why?
US or antibacterial gels
- gel’s viscosity prevents it from rolling off the convex nail surface.
How to minimize air bubbles in the gel used in dermoscopy?
- store the gel bottles upside down
- avoid shaking the bottle
- squeeze out a small amount of the gel before use so as to discard remnant dried gel
What will be the result if we use NPD without a liquid interface?
- The user will simply see a magnified clinical (not dermoscopic) image of the lesion
- no dermoscopic structures will be discernable
Main technique of polarized dermoscopes
Cross-polarization
Main advantages of cross-polarized system
- the 2 polarizers allow the dermoscope to preferentially capture the backscattered light from the deeper layers of the skin
- eliminates the necessity of a liquid interface
- does not require direct contact with the skin
Blood vessels & pink color are evident in PD or NPD, why?
PD (doesn’t require skin contact)
- pressure applied from the NPD scope against the skin can compress small blood vessels in a lesion, making it difficult to visualize them
Blue-white color (due to orthokeratosis), Milia-like cyst, Regression are more conspicuous under PD or NPD?
NPD
The PD instrument displays the melanin pigment with varying and darker shades of brown and blue compared with NPD
Some of the differences btw the images of PD & NPD are owed to?
Contact vs non-contract dermoscopy
Schematic representation of optical properties of light without the use of dermoscopy
Schematic representation of optical proper- ties of light during the use of contact NPD with a liquid interface
Relative differences btw NPD & PD
Schematic representation of optical properties of light during the use of polarized dermoscopy
Colors in dermoscopy depend on?
Location of melanin in the skin
Melanin is the main chromophore in pigmented skin lesions
Important determinants of the lesion color
- Melanin, the main chromophore in pigmented skin lesions (black to blue colors)
- Hemoglobin, in RBCs (pink to red colors)
- Collagen fibers in the dermis ( white color)
If melanin is located in the stratum corneum or immediately beneath it, the lesion would appear ___ on dermoscopy
Black
Melanin at the dermoepidermal junction (DEJ) would be perceived as ____, depending on its density
light brown to dark brown
Melanin in the dermis results in __?
shades of blue to gray
Colors in dermoscopy depending on the location of melanin in the skin
The stratum corneum, devoid of blood and melanin, appears ___?
Yellow
Areas with sebaceous differentiation can manifest__?
yellow hue
Blood vessels and vascular volume are responsible for __?
Red and pink hues
White color is due to __?
Depigmentation
fibrosis
alterations in the collagen matrix
keratin within cysts
Color of the lesion depending on the location of melanin
stratum corneum
vs
DEJ
vs
papillary dermis
vs
deeper dermis
Black (stratum corneum)
–
Brown (DEJ)
–
Gray (papillary dermis)
–
Blue (deeper dermis)
Jet-black color is usually due to?
congealed blood
Orange hues are usually due to?
serum present in erosions or superficial ulcerations
Basic colors in dermoscopy and anatomic background
Define pigment network (reticulation)
Grid-like or honeycomb pattern consisting of intersecting pigmented “lines” and hypopig- mented “holes”
Histopathologic correlation of pigment network
Melanin in keratinocytes and/or melanocytes along the epidermal rete ridges
What does presence of pigment network mean?
Name the exceptions
Presence of a network, indicates with few exceptions that the lesion is of melanocytic origin
Dermatofibroma, accessory nipple, lentigo
Typical vs atypical pigment network
- Typical: regularly meshed, composed of lines relatively uniform in width, homogeneous in color, lines become gradually thinner & fainter in pigmentation at the periphery.
Ass/w nevi (especially junctional)
- Atypical: irregularly meshed with lines that vary in width and degree of pigmentation, “holes” that are heterogeneous in area and shape, network often ends abruptly at the periphery
Ass/w melanoma,dysplastic nevi
Typical or atypical pigment network(pn)?
Typical pn
regular homogenous honeycomb-like pigment network thinning out at the periphery
Histopathological section of a typical or atypical pigment network(comment)?
Typical pn
There is more pigment per unit area overlying the rete ridge and this results in the dermoscopic observation of network lines. There is less pigment per unit area over- lying the supra-papillary plate and this corresponds to the dermoscopic holes in the network
Define pseudonetwork
In facial lesions, diffuse pigmentation is interrupted by nonpigmented adnexal openings, giving the appearance of a network
Define the type of pigment network seen in this nevus
Pseudonetwork
Pigment in the epidermis or dermis interrupted by follicular and adnexal openings on the face
Define structureless areas
Areas with a size >= 10% of the lesion’s surface area that are devoid of any discernible structures, such as globules, network, or regression structures (i.e., scars, peppering, granularity, or blue-white veil over flat areas)
Usually hypopigmented compared with the surrounding lesion, but not in comparison to the surrounding normal skin.
Focal structureless area within a lesion
vs
focal tan to light brown structureless areas at the periphery of melanocytic lesion
Common finding in benign nevi
vs
ass/w melanoma
Histopathologic correlation of structureless areas
Flattening of the rete ridge pattern and/or decrease in concentration of eumelanin +/- presence of pagetoid cells
It may also simply be due to a loss of contrast between the holes and lines of the network
Type of pigment network, structureless area?
Typical regular pn (periphery)
Central structureless area
Black dots upper part of lesion (arrows)
Dx: Compound nevus
Describe pn, structureless area in this lesion
Central atypical pn
Light brown structureless area periphery
Dx: Thin Melanoma
Define blotches
Dark brown to black, usually homogenous areas of pigment( >10% of lesion area) that obscures the ability to visualize underlying structures
- In nevi: homogenous, located towards the center
- In melanoma: heterogeneous, multiple hues, located off center
Describe the principal dermoscopic structure in this lesion
Dark central hyper-pigmentation area (blotch) that is obscuring the ability to visualize any underlying structures
Define dots
Small, round structures of <0.1 mm in dm that:
- have a red color when corresponding to blood vessels
- when due to melanin, their color ranges from black, brown, to blue-gray depending on the depth and concentration of the melanin in the skin (Tyndall effect)
Dots in nevi vs melanoma
- Nevi: located toward the center of the lesion, +/- overlie network lines
- Melanoma: not associated with the network, located toward the periphery
Define peppering or granularity or blue-white veil over flat (macular) areas
Tiny, blue-gray granules
sign of regression, can be seen in melanocytic & nonmelanocytic lesions
- In nevi: the area of regression usually encompasses <10% of the surface area of the lesion
- In melanoma: >50% of the surface area
Define globules
Round to oval structures that may be brown, black, blue-gray, or red with dm >0.1 mm
- Nests of melanocytes in the dermis
- Presence of aggregated globules >3 =>melanocytic origin of lesion
- In nevi: tend to be symmetrical, of similar size, shape, and color
- In melanoma: randomly distributed, different shape,size, color
Major dermoscopic finding in this lesion?
Globular pattern
globules display different sizes, shapes and colors, including browns, black, and blue-gray
Dx: Spitz nevus
Major dermoscopic finding in this lesion?
Globular pattern
globules correspond to nevomelanocytic nests in the dermis
Define streaks (pseudopods, radial streaming)
Radially arranged, linear projections of dark pigment (brown to black) at the periphery of the lesion that eminate from the tumor and radiate towards normal skin
- Spitz: streaks are arranged circumferentially around the entire perimeter
- Melanoma: located focally at the perimeter
Major dermoscopic finding in this lesion?
Multiple pseudopods at the periphery
Dx: SSM
Major dermoscopic finding in this lesion?
radial streaming (arrows) in the upper right portion of the lesion
Dx: SSM
Define negative pigment network
(aka reverse/inverse network)
Serpiginous interconnecting hypopigmented lines that surround irregularly shaped brown structures that resemble elongated and curvilinear globular structures
- Indicates melanocytic origin of lesion
- Ass/w: Spitz nevi, melanoma
Major dermoscopic findings in this lesion?
(left vs right side)
reticular architecture on the left side
negative pigment network on the right side
Major dermoscopic finding in this lesion?
homogenous architecture in the center
pseudopods distributed symmetrically along its entire perimeter
[Pseudopods (streaks) have a stalk that directly connects to the main tumor body]
Dx: Reed nevus
Major dermoscopic finding in this lesion?
peripheral rim of globules
globules are not directly connected to the lesion
Dx: Dysplastic nevus
Define chrysalis/crystalline
White shiny linear streaks that are seen ONLY with polarized dermoscopy
Ass/w: scars, dermatofibromas, BCCs, lichen-planus like keratosis
In melanocytic lesions DD btw: melanoma & Spitz nevi
Major dermoscopic findings in this lesion?
Multiple chrysalis-like structures (PD) especially in the upper left area
Blue-white veil (regression)
Major dermoscopic finding in this lesion?
Chrysalis-like structures
Dx: Melanoma
Define regression structures
White, scar-like depigmentation
often combined with or adjacent to blue-gray areas or peppering
DD: Melanoma (!!!), Lichen planus - like keratosis, Nevi
Define blue-white veil over palpable/raised areas
Irregular, confluent blue pigmentation with an overlying white “ground glass” haze
- DDx:
- Melanoma: Heterogeneous, prominent, asymmetrically shaped
- Blue nevi: covers the entire lesion
- Seborrheic Keratosis
- pBCC
Major dermoscopic finding in this lesion?
homogenous blue-white veil
encompassing the ENTIRE surface area of the lesion
Dx: Blue nevus
Define vascular structures
Pink hue (milky red areas) and isolated blood vessels with varying morphologies
- May be due to ^ vascular volume (vascular blush) or neoangiogenesis
Define milia-like cysts
Round whitish or yellowish structures that shine brightly
(like “stars in the sky”) under NP
Sometimes are pigmented & resemble globules
Ass/w: SKs(mainly), melanoma/nevi
Major dermoscopic finding in this lesion?
multiple milia-like cysts,
comedo-like openings and some fissures
Dx: SK
Define comedo-like openings
“Blackhead”-like plugs on the surface of the lesion
- Ass/w: SKs, nevi
Define ridges & fissures
Cerebriform surface resulting in gyri (ridges) and sulci (fissures)
- Ass/w: SKs
Major dermoscopic finding in this lesion?
multiple gyri and sulci creating a brain-like appearance
Dx: SK
Define fingerprint-like structures
Thin light brown lines that do not interconnect to form a meshwork pattern
Feature of lentigo or early seborrheic keratosis
Major dermoscopic finding in this lesion?
multiple parallel lines resembling finger-prints (dotted area)
and a moth-eaten border (arrows) at the periphery
Dx: SK
Define moth-eaten border
Concave invaginations of the lesion border
Feature associated with a solar lentigo
Define leaf-like areas
Brown to gray-blue discrete bulbous structures that often create shapes that resembles a leaf
Highly specific for BCC
Define spoke-wheel-like structures
Well-circumscribed brown to gray-blue-brown radial projections meeting at a darker brown central hub
Highly specific for BCC
Major dermoscopic finding in this lesion?
multiple spoke- wheel-like structures
Dx: pBCC
Major dermoscopic finding in this lesion?
leaf-like areas
Dx: pBCC
Define large blue-gray ovoid nests
Large, well-circumscribed areas, larger than globules
In the absence of a network are ^ specific for BCC
Major dermoscopic finding in this lesion?
Multiple blue-gray ovoid nests
Dx: pBCC
Define multiple blue-gray non-aggregated globules
Round well-circumscribed structures that resemble small ovoid nests
In the absence of a pigment network it suggests: BCC
Major dermoscopic finding in this lesion?
multiple blue- gray globules.
Dx: BCC
Define lacunae
Red, maroon, or black lagoons
Seen in angiomas and angiokeratomas
Major dermoscopic finding in this lesion?
blue black lacunae
Dx: Angiokeratoma
Major dermoscopic finding in this lesion?
multiple well- demarcated lacunae
Dx: Angioma
Histopathologic correlation of
globules
vs
streaks
- Nests of melanocytes in the dermis
- Confluent junctional nests of melanocytes
Histopathologic correlation of
Dots
vs
Peppering
- Aggregates of melanocytes or melanin granules
- Black – Upper epidermis , stratum corneum
- Brown – DEJ or spinous layer
- Gray – Papillary dermis
- Melanin deposited as intracellular (mostly within melanophages) or extracellular particles in the upper dermis
Histopathologic correlation of
pigment network
vs
pseudonetwork
- Melanin in keratinocytes and/or melanocytes along the epidermal rete ridges
vs
- Pigment in the epidermis or dermis interrupted by follicular and adnexal openings on the face
Histopathologic correlation of
structureless areas
vs
regression structures
- Flattening of the rete ridge pattern and/or decrease in concentration of eumelanin with/without the presence of pagetoid cells.
vs
- Scar-like changes: thickened fibrotic papillary dermis, sparse lymphocytic infiltrates, and variable numbers of melanophages
Histopathologic correlation of
milia-like structures
vs
chrysalis/crystaline
- Intraepidermal keratin cysts
vs
- increased or altered collagen in the superficial dermis (fibrosis)
Histopathologic correlation of
comedo-like openings
vs
fingerprint-like structures
- Concave clefts in the surface of the epidermis, often filled with keratin
vs
- thin, elongated epidermal ridges
Histopathologic correlation of
lacunae
vs
vascular structures
Dilated vascular spaces
vs
Dilated blood vessels in the papillary dermis
Histopathologic correlation of
negative pigmented network
vs
ridge and fissures
- thin elongated rete ridges that are accompanied by large melanocytic nests within widened papillary dermis.
vs
- Wedge-shaped clefts of the surface of the epidermis often filled with keratin
