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.
What is acral lentingous melanoma?
Arise on the palms and soles
slow growing discreate light brown or black macule with indistinct borders
Caucasian population ranging from 2-10% with the Afro-Caribbean population ranging from 60-72%.
What are subungal melanomas?
acral lentiginous melanomas arise in the nail region
diffuse discolouration or irregular pigmented longitudinal bands on the rail plate.
Hutchinson’s sign
Higher proportion in afro-caribbean skin
What are amelanotic melanomas?
These melanomas can mimic SCC or BCC and others. This is why the history is important.
What are the investigations for melanomas?
referred to dermatology under the 2- week wait system. need to excised with a 2mm margin. Vit D levels Histopathological features: Breslow thickness Ulceration status Mitotic rate Peripheral and deep margins Clark Level- indicates the anatomic plane of invasion Microscopic satellites
What is breslow thickness?
best prognostic factor in primary melanoma
measured in millimeters (mm) the distance between the overlying epidermal granular layer and the deepest level of invasion of the primary lesion.
What is the TMN staging for melanomas?
Stage 0: MM in situ, Breslow thickness not applicable
Stage 1: Localised disease with the Breslow thickness ≤1 mm. However, this category is subdivided into 1A and 1b depending on the Breslow thickness of 0.8 mm and ulceration status.
Stage 2: Localised disease, Breslow thickness 1.0-2.0 mm
Stage 3: Regional nodal and/or lymphatic metastases, Breslow thickness 2.0-4.0 mm
Stage 4: Represents distant metastases, Breslow thickness >4.0 mm
What are the recommended clinical margins for wide local excision melanoma?
MM in situ: 0.5-1 cm
Breslow depth ≤1.00mm: 1 cm
Breslow depth 1.01-2.00mm: 1-2 cm
Breslow depth >2.0mm: 2 cm
What occurs in lemph node biopsy and dissection?
Sentinel lymph node biopsy (SNLB), offered for >1mm breslow thickness
Total lymph node dissection: curative for metastases and those with palpable nodal disease without evidence of distant disease
How does the follow up differ for people with different staging of melanomas?
Patients who are stage 1B (Breslow thickness >0.8mm), they are followed up for 5 years. The follow up schedules is to see them every 3 months for the first 3 years and then every 6 months for the last 2 years.
What are possible differentials for melanoma?
Seborrhoeic keratosis: warty lesion, papule or plaque
Pigmented basal cell carcinoma: dark, irregular pigmentation, translucent, firm, telangiectasia
Dermatofibroma: benign nodule of fibrous tissue on lower legs, itchy inflammed
Pyogenic granuloma: Large papule attached to outside of skin, go away on their own
