Dermoscopy Flashcards
Describe how the description of local features varies from global features with regards to dermoscopy?
- Pigment network vs Reticular pattern
- Dots and Globules vs Globular Pattern
- Streaks/Pseudopods vs Starburst Pattern
- Blotches vs Homogenous Pattern
- Regression vs Multicomponent
There is also a Non-Specific pattern naevus.
(Local features various aspects of the naevus whereas the global features describe the overall impression)
Describe the colour changes that are seen in dermoscopy?
How does pigment network vary from typical to atypical naevi?
What lesions is it seen in?
Typical naevi have a regular uniform pattern.
Ayptical naevi are non-uniform, with heterogenous holes & end abruptly.
- Aquired melanocytic naevi
- Thin malignant melanomas.
How do globular patterns of pigmented lesions change between naevi and atypical naevi/malignant melanoma?
What lesions have globular patterns?
central = naevi
peripheral = malignant melanoma/Atypical
- Melanocytic naevi = especially compound and intradermal naevi
-
Cobblestone effects is a form of globular pattern and is seen in larger lesions:
- Congenital melanocytic naevi
- Seborrheic Keratoses
Describe how the starburst pattern (global) or streaks/peudopods (local) vary between typical and atypical lesions?
What lesions are these often seen in?
Symmetical peripheral arrangement = benign naevi & Spitz/Reed’s naevi
Irregular and patchy = malignant melanoma
Describe how a homogenous pattern (global) or blotches (local) change between typical naevi and ayptical naevi/malignant melanoma?
Central blotch/homogenous colour = typical naevus
Irregular or peripheral placed blotches = melanoma
In what 2 lesions is a blue/white veil seen?
Melanoma and Spitz/Reed Naevi
What pattern is this?
Multicomponent Pattern
(There are 3 or more components)
It is highly suggestive of melanoma
What pattern is this and how is it managed?
Non-specific pattern
Always consider a malignant melanoma.
What pattern is this?
Where is it seen?
How do you know when it is melanom?
Parallel Pattern
Seen acrally
Parralel Ridge Pattern is seen in melanoma - it is thicker and has eccrine gland openings on it.
Parralel Furrow Pattern is seen in typical naevi.
(Ridge is wrong)
What type of naevi is this?
Junctional melanocytic naevi
How do aquired melanocytic naevi change with age?
- In children and teenagers - there is a peripheral rim of brown globules as a sign of growth. (Pseudopods)
- Regular reticular and homogenous pattern in 30s+.
- Regress with age.
- Disappear in 70s and above.
What type of naevus is this?
Compound melanocytic naevus
(Usually have a raised central portion with a typical globular pattern)
What type of naevus is this?
What are its typical dermoscopic features?
Intradermal melanocytic naevi
- Globular pattern
- Comma-like blood vessels
- Cobblestone pattern
What is this?
What can happen to the central part?
Blue Naevus
The central part can undergo focal fibrosis. (aka Sclerosing blue naevi)
What is this?
Reed Naevus
Seen in adults - legs of females.
It has a starburst pattern.
What is this?
Spitz Naevus
- More commmon in children
- Amelanocytic version of the Reed naevus.
What type of naevi are these?
Atypical Naevi (aka Clark’s naevi)
(Containing similar patterns to melanoma)
NOTE: Establish the predominant pattern of the individual or if they have many atypical naevi on examination.
What percentage of melanoma come from aquired naevi?
Describe how you can tell if a melanoma might be growing from a naevus on dermoscopy?
50%
- Look for the dermoscopic island - a well circumscribed area of uniform dermoscopic pattern that differs from the rest of the lesion - this is most likely the melanoma
Describe the 3 Point Checklist
- Assymmetry of colours and structures
- Atypical or irregular pigment network
- Blue-White Veil
A score of 2 out of 3 means that a biopsy needs to be performed.
What are the 10 most common dermoscopic features of malignant melanoma?
- Atypical pigment network
- Negative (inverse) pigment network
- Focal Streaks (pseudopods/radial streamin
- Eccentric blotch
- Atypical dots/globules
- Blue-white veil
- Crystalline (chrysalis) structures
- Regression structures
- Atypical vascular structures (Polymorphous vessels)
- Multiple colours
Analyse this melanoma using the 3 point checklist
- Assymetrical colours and structures
- Atypical pigment network
- No blue with veil
THEREFORE
2/3
Analyse this melanoma using the 3 point checklist
- Asymmetrical colours and structures (blotches, atypical streaks, peripheral globules)
- Atypical pigment network
- Possible blue-grey veil
This is a multicomponent pattern
3/3
Describe this using the 3 Point Checklist
- Normal colour and structure
- Irregular pigment network
- Blue-Grey Veil
2/3
Dermoscopically, how can you determine if hypopigmented or amelanotic lesion is a melanoma?
- Looks like a BCC/SCC
- Foci of pigment remnants - look for blue or gray areas.
- Atypical vascular pattern - presence of polymorphous blood vessels (dotted, hairpin and irregular linear vessels.)
- More than one shade of pink.
- White shiny lines - only seen on polarised dermatoscopes.
What percentage of nodular melanomas are invasive melanomas?
10-15%
How do nodular melanomas present?
Rapidly growing papules or nodules that ulcerate or bleed.
Why are nodular melanomas difficult to diagnose at an early stage on dermatoscope?
The normal features of a superficial spreading malignant melanoma are lacking.
What are the typical dermoscopic features of a nodular melanoma?
- Blue gray structures
- White polarized lines (chrystalline structures).
- Irregularity of colour
- Atypical vascular pattern
How are the “rete ridges”on the face different?
How does this affected dermoscopy of pigmented lesions?
Rete Ridges are flat on the face and thus a “pseudonetwork” = a broad mesh with wider holes.
The pseudonetwork does not distinguish between melanocytic and non-melanocytic lesions
What is a way of distinguishing between benign pigmented lesions vs lentigo maligna?
Lentigo maligna = poorly defined borders.
Benign pigmented lesions ahve well defined borders.
What are the 5 suspicious dermoscopy findings in lentigo maligna?
- Asymmetric follicular openings (Signet Ring Structures)- 1st change in lentigo maligna. It is due to the descent of the melanoma cells into individual hair follicles
- Annular-granular pattern
- Dark rhomboidal structures
- Dark homogeneous areas
- Pink-reddish areas - indicates invasion and tumour progression.
What are the 3 benign pigmented patterns in acral skin?
- Parallel furrow pattern - Most common (50%)
-
Lattice-like pattern
- Arch areas of the sole and/or at the peripheral areas of palms and soles
-
Fibrilar pattern
- Parallel fine lines crossing the skin markings in a slanting direction
- Most common on high pressure areas of feet
What sort of benign acral pattern is this?
Parallel Furrow Pattern
What sort of benign acral pattern is this?
Lattice-like pattern
(Most commonly seen on the arches of the feet)
What sort of benign acral pattern is this?
Fibrilar pattern
(Most commonly seen on the high pressure areas of the feet)
What are the 2 Dermoscopic features of acral malignant melanoma?
- Parallel ridge pattern
- Irregular diffuse pigmentation
What sort of acral pattern is this for malignant melanoma?
Parallel ridge pattern
(Eccrine glands are in the ridge)
What sort of acral pattern is this for malignant melanoma?
Diffuse Irregular Pattern
What sign is seen here?
What other interesting thing about this nail makes it a malignant melanoma?
Hutchinson’s sign - periungual pigmentation on the proximal nail fold.
The pigmentation gets wider towards the base meaning that the lesion is enlargening.
How can you tell the difference between a benign melanocytic naevus and a Malignant Melanoma in a nail?
Malignant Melanomas in a nail are heterogenous in colour, thickness and spacing with a subtle disruption of parallelism, only noticed with dermoscopy.
What are the 4 features of a pigmented seborrhoeic keratoses?
- Comedo-like openings
- Milia like cysts
- Cerebriform pattern
- Fingerprint-like structures
What is the hallmark feature of a non-pigmented sebhorreic keratosis?
Hairpin vessels - thin elongated vessels surrounded by whitish halo
What are the features of a dermatofibroma?
A central white scar-like area and peripheral thin pseudonetwork
What are the dermoscopic features of BCC?
- Arborising vessels
- Blue-Gray Ovoid nests and globules
- Leaf-like structures
- Spoke-wheel areas
- Multiple erosions/ulceration
What features of a BCC do you see here?
Arborising vessels
Blue ovoid nests
Spoke Wheel Areas
What are the dermoscopic features of a sebaceous hyperplasia?
- Sebaceous gland lobules with peripheral telangiectasias.
- Crown vessels - the telangiectasia do not cross over the lobules.
- Central punctum
What are the dermoscopic features of cherry haemangiomas on dermoscopy?
Dark or black on thrombosed lesions called (Lakes or Lacunae)
What are the dermoscopic features of a pyogenic granuloma?
Does it need biopsy?
Reddish or pinkish homogeneous areas intersected by white lines
(“white rail lines”)
Yes it needs biopsy because it can look like a nodular amelanotic melanoma.
What are the features of an Angiokeratomas on dermoscopy?
- Dark Lacunae (Lakes) with a white-veil background.
- Erythema on the periphery
What are the features of an solar keratosis & IEC on dermoscopy?
A=Solar Keratosis
B,C & D =Bowen’s Disease
-
Solar Keratosis = a white or yellowish halo surrounding the hair follicular openings over a background of erythema with a variable degree of scale.
- Often called a Strawberry Pattern
- IEC = erythematous scaly areas with glomerular vessels and, sometimes, dotted vessels
