Step 2: Methods to DD btw melanoma & benign melanocytic nevi Flashcards
Colors in benign lesions vs melanoma
1-2
vs
+3
5-6 colors => 95% specificity for melanoma
What colors have the greatest impact on melanoma dx?
- Red
- White
- Blue/gray
Much more suspicious than brown
Red color
vs
Black
vs
White
vs
Gray
Hb in the skin
vs
melanin in stratum corneum or epidermis
vs
fibrosis or hyperkeratosis
vs
melanin in papillary dermis
Comma vessels are ass/w?
Benign (intradermal) nevi
Dermoscopic equivalent of ^blood volume within a lesion
Milky red areas
Gray colored granularity in benign vs malignant lesions
< 10% of lesion surface area(LSA)
vs
> 50%
Melanin located in stratum corneum vs below stratum corneum
Can be tape stripped off
vs
cannot
Tape stripping method
Blotches
vs
irregular black dots
in melanoma correspond to?
melanin in all layers of the epidermis and dermis
vs
pagetoid spread
What does pagetoid spread mean?
“upward spreading” of abnormal cells in the epidermis
Characteristic color of benign melanocytic lesions
Light brown
Light brown color
+
atypical vessels
should raise suspicion for?
Hypomelanotic melanoma
MC dermoscopic manifestation of melanoma in fair-skinned individuals
- Few colors & structures
- Light brown color
Name the dermoscopic melanoma-specific structures
- Atypical pigment network
- Negative network
- Irregular streaks (radial streaming, pseudopods)
- Atypical dots & globules
- Blue white veil (BWV)
- Chrysalis-like structures
- Regression structures
- Atypical vessels
- Atypical blotch
- Peripheral brown structureless areas
- 5-6 colors
Which of the melanoma specific structures has the highest OR?
Peripheral brown structureless areas
28 (!!)
Pigment network in
benign nevi
vs
melanoma
- Relatively uniform in thickness, color
- Thinning at the periphery
vs
- heterogeneous
- color variegation
- abrupt cutoff at periphery
Define negative network
serpiginous interconnecting hypopigmented lines that surround irregularly shaped pigmented structures
Negative network DDx
- Congenital nevi
- Acquired nevi (eg, Spitz)
- Melanoma
Negative network
benign lesions
vs
melanoma
- symmetrically distributed
- involves ENTIRE lesion
vs
- asymmetrically distributed
- focally within the lesion
Lesion with regular streaks in an adult. Management?
Excisional biopsy
bcz some melanomas present with relatively regular streaks
MC types of melanoma in childhood(rare) ?
Nodular +/- amelanotic
( thus they do not display any streaks)
Lesions with streaks in childhood, management?
Closely monitored or excised
Blue white veil over a flat or raised part of the lesion, corresponds with regression?
Flat
Regression structures include?
- Blue-white veil over flat part of lesion
- Peppering/granularity
- Scar-like depigmentation
Regression structures seen in benign lesions vs melanoma
< 10% of LSA
vs
> 50%
Homogeneous blue-white veil in entire lesion
vs
homogeneous BWV in central part
vs
Irregular BWV in melanocytic lesion
Blue nevus
vs
combined nevi, Spitz
vs
melanoma
Chrysalis-like structures DDx
- Melanoma
- Spitz nevi
- BCC
- Dermatofibroma
- LPLK
Regular vs irregular blotches
- Symmetrically in the center
- can be stripped off
- black uniform color, “lamella”
vs
- located off center
- cannot be stripped off
- multiple shades of color
Peripheral brown structureless areas correlate with?
- Flattening of DEJ
- Presence of pagetoid cells
Describe the major dermoscopic findings in this lesion
Dx?
- Multiple colors ( “chaos”)
- atypical pigment network
- Irregular dots & globules
- irregular blotch
- regression structures
- atypical vessels
- milky red areas
Melanoma
Describe the major dermoscopic findings in this lesion
Dx?
- One color ( light brown)
- Typical pn
- Few typical globules
Benign nevus
Describe the major dermoscopic findings in this lesion
Dx?
- Comma shaped vessels
Benign intradermal nevus
Describe the major dermoscopic finding in this lesion
Dx?
- Polymorphous vessels
- Milky red areas
Hypomelanotic melanoma
Describe the major dermoscopic findings in this lesion
Dx?
Extensive regression with:
- granularity/peppering
- scar-like depigmentation
How to differentiate BWV from chrysalis-like structures
BWV much more evident in NPD
vs
Chrysalis in PD
Describe the major dermoscopic findings in this lesion
Dx?
- Multiple colors
- Atypical pn ( thick lines, small, holes, abrupt cutoff periphery)
- Irregularly distributed streaks & globules
- Regression structures
- Chrysalis
Melanoma
Describe the major dermoscopic findings in this lesion
Dx?
- Atypical dots & globules
- Atypical blotches
- multiple colors
Melanoma
arrow corresponds to pagetoid cells & nests in epidermis
Describe the major dermoscopic finding in this lesion
Dx?
- Typical pn
- One color, (light brown)
Benign nevus
Describe the major dermoscopic findings in this lesion
Dx?
- Atypical pn
- Peripheral brown structureless area
Melanoma
Describe the major dermoscopic finding in this lesion
Dx?
Negative network centrally
Benign nevus
Describe the major dermoscopic finding in this lesion
Dx?
Focal negative network (lower part)
Melanoma
Highly suggestive of Spitz/Reed nevus?
Streaks around the entire perimeter
Describe the major dermoscopic findings in this lesion
Dx?
- 2 colors, black/brown
- Central blotch
- Regular peripheral streaks & globules
Spitz/Reed nevus
Describe the major dermoscopic finding in this lesion
Dx?
Focally distributed streaks
Microinvasive melanoma
Describe the major dermoscopic finding in this lesion
Dx?
- Typical pn
- Black dots regularly distributed
Benign nevus
Describe the major dermoscopic finding in this lesion
Dx?
Typical globular pattern throughout the lesion
Benign nevus
Describe the major dermoscopic findings in this lesion
Dx?
- Peripheral pn
- Central globules
Benign nevus
Describe the major dermoscopic finding in this lesion
Dx?
Peripheral rim of globules
Benign nevus
Identify the most prominent dermoscopic finding in image A vs B
Dx? (Same lesion)
A) NPD: Blue-white veil
vs
B) PD: Chrysalis-like structures
Melanoma
Describe the major dermoscopic finding in this lesion
Dx?
- Central black blotch, “lamella”
- Typical pn
Benign nevus
Describe the major dermoscopic findings in this lesion
Dx?
- Central structureless area
- Peripheral pn
Benign nevus
Describe the major dermoscopic finding in this lesion
Dx?
Peripheral brown structureless area
Melanoma
Which one has better diagnostic accuracy:
analysis-based algorithms
vs
pattern analysis
Pattern analysis (slightly better)
Usage of both methods optimizes diagnostic outcome
Asymmetry is a prerequisite for melanoma dx
T/F ?
False
Some melanomas may manifest dermoscopic symmetry
Dermoscopic “definition” of melanoma
- Lesions that deviate from benign nevus patterns
- Manifest at least 1 out of 10 melanoma-specific structures
Melanoma until proven otherwise
Schematic drawings of the 10 benign nevus patterns
Features of diffuse reticular pattern
- Diffuse homogenous network
- uniform thickness, color of network lines
- Network fading at periphery
Diffuse reticular pattern is MC seen in..?
- Acquired nevi, individuals with darker phenotype
- Congenital nevi, > lower extremity
Features of patchy reticular pattern
- Focal patches of homogeneous network
- surrounded by homogeneous structureless areas
Patchy reticular pattern is MC seen in…?
- Acquired nevi, torso
- Superficial congenital nevi, lower extremity
Features of peripheral reticular with central hypopigmentation
- uniform network at the periphery
- central homogenous, hypopigmented, structureless area
Features of peripheral reticular pattern with central hyperpigmentation
- uniform network at the periphery
- central homogenous, hyperpigmented structureless area or blotch
Peripheral reticular pattern with central
hyperpigmentation
vs
hypopigmentation
is MC seen in?
Acquired nevi in:
dark skin phenotype
vs
fair skin