Pigmented skin lesions Flashcards
What are the main types of benign melanocytic lesions?
Ephilides, lentigines, naevi
What is the difference between each of the main types of melanocytic lesion?
Ephilides - increased melanin production with normal melanocyte number
Lentigines - increased number of melanocytes with normal melanin production
Naevi - increased basal melanocytes (nests) with downgrowths at the DEJ
What are the visual differences between an ephilides and lentigines?
Lentigines are usually darker and larger than ephilides and may darken with UV exposure but do not fade in water
How do melanocytic naevi develop?
From melanocytes which fail to mature/migrate in utero
What are the three classifications of melanocytic naevi?
Junctional, compound and intradermal
How do junctional naevi appear?
Brown macules
How do compound naevi appear?
Brown papule (usually light brown)
Is hair on a naevi a good or a bad sign?
Good sign
How to intradermal naevi appear?
Skin coloured/light brown papule
What are congenital naevi?
Benign proliferations of melanocytes in dermis & epidermis
What are the clinical and histological differences between acquired and congenital naevi?
Congenital naevi are usually larger and more raised than acquried naevi, they become more wrinkled and elevated with growth & there is a higher risk of melanoma in large naevi
What is the relationship between atypical/dysplastic naevi syndrome and risk of melanoma?
As the number of dysplastic naevi increases so does the risk of melanoma
What is naevus spilus?
A light brown macule which is speckled with smaller, darker macules/papules
What is the typical dermatoscope appearance of malignant melanoma?
Atypical pigment network, black dots, irregular streaks, blue/white veil, white regression zone, hairpin vessels
What is the typical dermatoscope appearance of a benign naevus?
Pale homogenous centre OR fading border with featureless pale centre, etc
Where is the most common site of superficial spreading melanoma on men and woman respectively?
Men - trunk
Woman - legs
What is the natural history of a superficial spreading melanoma?
Macule with irregular border and colour which may have been increasing in size for years before developing a nodule
What is the pace of development of a nodular melanoma?
Rapidly
Do nodular melanomas have surrounding macular pigmentation?
No (but superficial spreading melanomas do)
What is a lentigo maligna melanoma?
Invasive melanoma developing within a lentigo maligna
What is hutchinson sign? What is it a sign of?
Pigmented extension into the nail fold. Acral lentiginous malignant melanoma
Which groups of patients usually get acral lentiginous malignant melanoma?
Elderly patients, asian & african patients
Where does acral lentiginous malignant melanoma usually present?
Soles, palms or nails
What is an amelanotic melanoma?
A melanoma with absent or minimal visible pigment
