Module 5: Melanocytic Nevi Flashcards
New classification of nevi based on Dermoscopy
cobblestone pattern globular p reticular p homogenous blue p starburst p not specific p
New classification - pigment distribution
Uniformly pigmented Central hyper pigmented central hypo pigmented eccentric hyper pigmented eccentric hypopigmented multifocal hyper/ hypo pigmented
New classification - color
Light brown Dark brown Red White Blue Black Grey
2 main categories of melanocytic nevi
Congenital
Acquired
Categories of congenital nevi
Large
Medium
Small
Categories of acquired nevi
Junctional, compound, dermal
Spitz
Blue
Other
Incidence of congenital nevi
Likely 1% or lower
Risk of melanoma in CN?
Small - medium 0-5% lifetime risk
Giant 5-15%
Origin of melanoma in CN
Dermis
Congenital nevis, dermoscopic features
- Asymmetry
- Pattern
a. Multicomponent
b. Globular (cobblestone)
c. reticular
d. Homogenous - Pigmentation
a. Uniform
b. Hypo/ hyper-pigmented
Congenital nevis, additional dermoscopic features
Hypertrichosis
Perifollicular hyper/ hypo-pigmentation
Vessels
Definition giant congenital nevus
> 20 cm adult
6 cm birth
9 cm birth, head
Management giant congenital nevus
- MRI to r/o neurocutaneous melanosis
- Early surgery if appropriate
- Follow up examination every 6 months.
Management small/ medium congenital nevi
If suspicious features excise If change in lesion excise if difficulty with documentation excise If unable to do full excision do partial excision of suspicious area. If unable to excise follow up.
What is histopathological correlate of globular pattern?
Nests of melanocytes at the Dermoscopy-epidermal junction and dermis
What is dermoscopic hallmark of nevi in childhood?
Globular pattern
What types of nevi contain globular pattern?
Small congenital
compound
dermal
Arguments for common histiogenetic background globular nevi
- Histopath features of small CMN, compound nevi, dermal nevi often indistinguishable.
- All 3 types characterized by same morphologic pattern
- Histopathologic studies report on high number compound or dermal nevi in early childhood and late adulthood.
New classification globular nevi
- Previously characterized as small congenital nevi, compound nevi +/- dysplasia, dermal nevi.
- Development dt endogenous pathway
- Life-long persistence
What is hallmark of Nevis in adults with development at puberty
Reticular pattern
Reticular pattern, histopath correlation
proliferation of malanocytes along elongated retentions ridges
In what type of nevi is reticular pattern typically seen?
Junctional nevi +/- dysplasia
Association between nevus and skin type
ST I. Light brown, central hypo-pigmentation
ST II. Light brown, multi-focal hyper/ hypo-pigmentation
ST III. Light brown, multi-focal hyper/ hypo-pigmentation
ST IV. Dark brown, central hyper-pigmentation.
Reticular nevi pathway
“True” AMN
Development in early adolescence, exogenous pathway (UV induced), disappearance later in life dt involution and or regression.
New classification reticular nevi
- Previously categorized as acquired melanocytic nevi, junctional nevi +/- dysplasia.
- Development dt exogenous pathway.
- Involution.
Starburst pattern histopath correlation
vertically arranged well defined junctional melanocyte nests with signs of maturation in deeper parts
Starburst pattern hallmark of …
Spitz and Reed nevi
Starburst pattern represents …
transitory pattern in evolution of pigmented Spitz nevi
globular > starburst > homogenous > involution
New classification Starburst nevi
Previoiusly pigmented spitz or reed nevus
Development ? endogenous
Evolution
New classification site related nevi
Parallel pattern - aural nevi
Band like pattern- sublingual nevi
Pseudo network pattern - facial nevi
Globular reticular grey blue pattern - mucosal nevi
New classification nevi with special features
Combined nevus Halo nevus Hemosiderotic target nevus (traumatized nevus) Meyerson nevus Recurrent nevus
New terminology dysplastic (Clarke) nevus
large acquired nevus
> 5 mm
