5. Melanocytes:
In stratum basale
Pale “halo” of cytoplasm
Neural crest
Produce melanin and pass it
on to nearby keratinocytes
Melanin covers nuclei of
nearby keratinocytes
Skin colour depends on
melanocytes activity, rather
than the number present
6. A tumour arising from
melanocytes of the
basal layer of the
epidermis
Less commonly –
uveal tract (eye) and
meningeal
membranes
7. MM is the only common life –
threatening problem in
dermatology.
Primary cutaneous melanoma may
develop in precursor melanocytic
nevi (common acquired, congenital
and atypical types ), although more
than 50 % of cases are believed to
arise without apreexisting
pigmented lesion .
8. The cause is unknown.
Excessive exposure to sunlight
Genetic predisposition
9. EpidemiologyEpidemiology
Melanoma accounts for only 4 % of all
skin cancers , however ,it causes the
greatest number of cancer-related
deaths .the incidence of MM is
increasing more rapidly that of any other
cancer, making it the 5th
most common
invasive cancer in men and women .
10. 1-Excessive sun exposure.
2-Race : MM is more common in
white races .
3-Previous cutaneous MM.
4- Family history of MM.
5- Increase numbers of
acquired nevi.
6- Presence of potential
precursors of MM e.g
dyeplastic nevi and CMN.
11. Occur anywhere on the skin
Females (commonest is lower leg)
Males ( back).
Early melanoma is pain free. The
only symptom if present is mild
irritation or itch.
12. GLASGOW SYSTEM
Major:
Change in size
Irregular pigment
Irregular outline
Minor:
Diameter >6mm
Inflammation
Oozing/bleeding
Itch/altered sensation
AMERICAN ‘ABCDE’
SYSTEM
Asymmetry
Border
Colour
Diameter
Examination
13. Evolving; a
mole or skin
lesion that
looks
different
from the rest
or is
changing in
size, shape,
or color
Evolving; a
mole or skin
lesion that
looks
different
from the rest
or is
changing in
size, shape,
or color
15. The most common type
of MM in the white-
skinned population –
70% of cases
Commonest sites –
lower leg in females
and back in males
In early stages may be
small, then growth
becomes irregular
16. Commoner in males
Trunk is a common site
Rapidly growing
Usually thick with a
poor prognosis
Black/brown nodule
Ulceration and
bleeding are common
17. In white-skinned
population this accounts
for 10% of MMs, but is
the commonest MM in
nonwhite-skinned
nations
Found on palms and
soles
Usually comprises a flat
lentiginous area with an
invasive nodular
component
18. Rare
Often diagnosed late –
confusion with benign
subungal naevus,
paronychial infections,
trauma
Hutchinson’s sign –
spillage of pigment onto
the surrounding nailfold
19. Occurs as a late
development in a
lentigo maligna
Mainly on the face in
elderly patients
May be many years
before an invasive
nodule develops
22. Level I: Lesions involving only the epidermis (in
situ melanoma); not an invasive lesion.
Level II: Invasion of the papillary dermis but does
not reach the papillary-reticular dermal interface.
Level III: Invasion fills and expands the papillary
dermis but does not penetrate the reticular dermis.
Level IV: Invasion into the reticular dermis but
not into the subcutaneous tissue.
Level V: Invasion through the reticular dermis into
the subcutaneous tissue.
Clark Classification (Level of Invasion)
23. The Breslow thickness is
the single most
important prognostic
variable (distance in mm
of the furthest tumour
cell from the basal layer
of the epidermis)
Breslow
depth
5 year
survival
In situ 95-100%
<1mm 95-100%
1-2mm 80-96%
2.1-4mm 60-75%
>4mm 50%
24. Scalp lesions worse prognosis, then
palms and soles, then trunk, then
extremities
Younger women appear to do better than
either men at any stage or women over
50
Ulceration of the tumour surface is a high
risk factor
26. Keep out of the strong midday sun
(between 10 am and 3 pm)
Remember clothing is an effective
sunscreen (particularly fine
woven cotton clothing)
Use hats in the sun, particularly
broad brimmed hats
Use a sunscreen to protect from
UVR.
27. Sunscreens should be liberally applied and
reapplied every two hours if exposure to the
sun continues.
Protect children and infants from strong sunlight
at all times. Use a sunscreen with a high sun
protection factor number (>15) .
Avoid using sunbeds and sunlamps.
Notas del editor
Important to differentiate the navi from early malanoma
5% familial – genes arnd chrmosome 9p21 appears to be involved.
1 major and 1 or more minor should be considered for exicion and diagnostic biopsy.