ACQUIRED Pigmented Lesions Flashcards
Which is this lesion? Small (<5 mm) welldemarcated light brown macules Sites: sun-exposed skin
Ephelides
Freckles
Which is this lesion? Hairy, light brown macule/patch with a papular verrucous surface Sites: trunk and shoulders, onset in teen yr
Becker’s Nevus
Which is this lesion? Symmetrical hyperpigmentation on sun-exposed areas of face (forehead, upper lip, cheeks, chin)
Melasma
Which is this lesion? Variegated macule/ papule with irregular distinct melanocytes in the basal layer Risk factors: family history
Atypical Nevus
Dysplastic Nevus
Which is this lesion? well circumscribed, round, uniformly pigmented macules/papules <1.5 cm. commin mole.
ACQUIRED NEVOMELANOCYTIC NEVI
Which is this lesion? Well-demarcated
brown/black macules
Sites: sun-exposed skin
Solar Lentigo
Liver Spot
ACQUIRED NEVOMELANOCYTIC NEVI
Clinical Feature. Average number. and stages
- average number of moles per person: 18-40
* 3 stages of evolution: junctional NMN, compound NMN, and dermal NMN
Junctional NMN. Age of Onset
Childhood
Majority progress to
compound nevus
Junctional NMN. Clinical Feature
Flat, regularly bordered, uniformly tan-dark
brown, sharply demarcated macule
Junctional NMN. Histology
Melanocytes at dermal-epidermal
junction above basement membrane
Compound NMN. Age of Onset
Any age
Compound NMN. Clinical Feature
Domed, regularly bordered, smooth, round,
tan-dark brown papule
Face, trunk, extremities, scalp
NOT found on palms or soles
Compound NMN. Histology
Melanocytes at dermal-epidermal
junction; migration into dermis
Dermal NMN.Age of Onset
Adults
Dermal NMN. Clinical Feature
Soft, dome-shaped, skin-coloured to tan/
brown papules or nodules
Sites: face, neck
Dermal NMN. Histology
Melanocytes exclusively in dermis
ANMN Management
new or changing pigmented lesions should be evaluated for atypical features which could indicate a
melanoma
• excisional biopsy should be considered if the lesion demonstrates rapid change, asymmetry, varied
colours, irregular borders and persistent pruritus or bleeding
Atypical Nevus
(Dysplastic Nevus) Pathophysiology
Hyperplasia and proliferation of melanocytes extending beyond dermal compartment of the nevus Often with region of adjacent nests
Atypical Nevus
(Dysplastic Nevus) Epidemiology
>5 atypical nevi increase risk for melanoma Numerous dysplastic nevi may be part of familial atypical mole and melanoma syndrome
Atypical Nevus
(Dysplastic Nevus) Clinical Course and Management
Follow with baseline photographs for changes Excisional biopsy if lesion changing or highly atypical Close surveillance with whole body skin examination
Ephelides
(Freckles) Pathophysiology
Increased melanin within
basal layer keratinocytes
secondary to sun exposure
Ephelides
(Freckles) Epidemiology
Skin phototypes I-II most
commonly
Ephelides
(Freckles) Clinical Course and Management
Multiply and darken with sun exposure, fade in winter No treatment required Sunscreen and sun avoidance may prevent the appearance of new freckles
Solar Lentigo
(Liver Spot) Pathophysiology
Benign melanocytic
proliferation in dermalepidermal
junction due to
chronic sun exposure
Solar Lentigo
(Liver Spot) Epidemiology
Most common in Caucasians
>40 yr
Skin phototypes I-III most
commonly
Solar Lentigo
(Liver Spot) Clinical Course and Management
Laser therapy, shave excisions,
cryotherapy
Becker’s Nevus Pathophysiology
Pigmented hamartoma with
increased melanin in basal
cells
Becker’s Nevus Epidemiology
M>F
Often becomes noticeable at
puberty
Becker’s Nevus Clinical Course and Management
Hair growth follows onset of
pigmentation
Cosmetic management (usually too
large to remove)
Melasma Pathophysiology
Increase in number and
activity of melanocytes
Associated with estrogen
and progesterone
Melasma Epidemiology
F>M Common in pregnancy and women taking OCP or HRT Risk factors: sun exposure, dark skin tone Can occur with mild endocrine disturbances, antiepileptic medications and other photosensitizing drugs
Melasma Clinical Course and Management
Often fades over several mo after stopping hormone treatment or delivering baby Treatment: hydroquinone, azelaic acid, retinoic acid, topical steroid, combination creams, destructive modalities (chemical peels, laser treatment), camouflage make-up, sunscreen, sun avoidance
