Melanoma and benign lesions Flashcards
What are congenital melanocytic naevi?
Consist of proliferations of benign melanocytes that may be intraepidermal, dermal, or both.
Rarely, lesions appear after birth or within 2 years and are referred to as tardive congenital naevus.
CMN can present as single or multi-shaded, round or oval shaped pigmented patches. They may have increased hair growth (hypertrichosis). The surface may be slightly rough or bumpy.
small <1.5cm, medium 1.5-20cm, large 20-40cm, giant >40cm
What conditions are associated with CMNs?
Itchy
neurological abnormalities such as seizures
Risk of melanoma
Larger the nevus the greater the risk
What factors contribute to the formation of an acquired melanocytic naevi (mole)?
Number increases with age, peak in 30s UV exposure BRAF mutations Blistering processes Increased hormone levels
What is a junctional naevus?
Nests of naevus cells at the junction of the epidermis and the dermis.
Macular lesion with a uniformly pigmented medium to dark brown colour.
It can be located anywhere in the body, common on trunk and extremities.
What is a compound naevus?
Variable degrees of elevation, either oral or round papule that are brown or light brown in colour with symmetrical shape.
Nests of naevus cells at the epidermal-dermal junction as well as within the dermis.
What is an intradermal naevus?
More elevated and can be light brown to flesh coloured nodules. The surface is usually smooth but can also appear papilomatous.
One or few hair shafts may project from the surface. Naevus cell nests in the dermis.
What are atypical naevi?
5mm or larger, have an irregular or poorly defined border, variably pigmented, asymmetrical and may be flat or raised
risk factor for melanoma and, to a lesser extent, potential precursors of melanoma
Sporadic or familial, more prevalent in younger ages
1.45 risk of melanoma for one, 6.36 for 5
Manage with excision, check moles regularly and sun protection
What is a halo naevus?
Melanocytic naevus surrounded by a white ring or halo around it. Almost half undergo total clinical and histological regression
Prevalence of 1%
Solitary or multiple
Autoimmune response to neavus cells
What is a blue neavus?
benign melanocytic naevus that are blue, blue-grey comprised of dermal melanocytes
Common in females, adolescence
Watch for melanoma, don’t require treatment
What are the risk factors for melanoma?
Family history, light skin, red hair, inability to tan/burn, increasing age
Multiple atypical naevi, large congenital naevi, personal history
Sun exposure, phototherapy, iatrogenic or immunosuppression, tanning beds
What is the ABCDE algorithm to describe melanoma?
Asymmetry Borders- irregular Colour- variably pigmented colour Diameter >6mm Evolution- mole changing shape and colour
What is melanoma in situ?
Earliest stage, atypical naevus like lesion
macular with an irregular outline and variable pigmentation
Melanocytes are confined to the epidermis
What are superficial spreading melanomas?
60-70% of all melanomas
Commonly seen on the trunks for men and legs in females.
atypical naevus which progressively becomes
more irregular in shape and colour.
The lesion will become palpable with development of a nodule.
What is nodular melanoma?
10-20% of melanomas
fast-growing subgroup of melanoma and are usually the thick tumours at diagnosis
Ulceration and bleeding
M>W
What is letingo maligna melanoma?
slow growing radial growth phase and it may take months and years.
present as flat, brown or black, irregularly shaped lesion and is usually found on chronically sun exposed areas of the skin (e.g. face, neck, forearms) in the elderly.
