Malignant melanoma is a serious type of skin
cancer. Proliferation of benign melanocytes results in benign
melanocytic naevi (moles) and lentigines (freckles). Malignant melanoma
is due to uncontrolled, cancerous growth of transformed melanocytes.
Who
is
at risk? Although
melanoma can occur in all races, white skinned individuals are most at
risk. It
is believed that excessive sun exposure is a major risk factor for
development
of melanoma. The incidence of malignant melanoma is highest among fair
skinned
individuals living in sunny climates (Australia, southern United States
etc).
Other risk factors include: sun exposure and sunburnduring childhood, family history of
melanoma and the
presence of large numbers of moles or abnormal moles on the skin
.
Types
of
melanoma When the
melanoma cells are confined to the epidermis only, the lesion is called
melanoma in situ. When the melanoma cells are found below the basement
membrane
it is known as invasive melanoma. These invasive melanomas can have a
horizontal growth phase (superficial spreading melanoma) or a vertical
growth
phase (nodular melanoma). Rarer types of melanoma include: desmoplastic
melanoma, mucosal melanoma, acral lentiginous melanoma, amelanotic
melanoma and
melanoma of the eye.
Metastatic
disease
Invasive
melanoma may spread
to other tissues via the lymphatic system or via the blood stream.
Organs such
as the brain and the lungs may be affected. The chance of metastasis
mainly
depends on the penetration of melanoma cells into the skin at the site
of the
primary melanoma lesion. Thus, early detection and -removal of
melanomas is of
vital importance!
Early detection of melanoma Most
melanomas present as a changing freckle or mole. A change in shape or
colour
(or both) may be detected. In many cases dark pigment appears that may
be
black, grey or blue. However, hypopigmented, skin coloured or red
elements may
also occur in a melanoma. Growth of moles may also be a sign of
malignant
transformation as are signs such as pain, itch or bleeding. Doctors use
checklists when examining moles in order to determine the melanoma risk
of
individual moles. It should be noted that not all melanomas show these
characteristics or they present only with a few of the characteristics
mentioned below. On the other hand, not all moles that show changes
prove to be
malignant.
Glasgow
7-point checklist
ABCD-rule
Major features:
change in size irregular
shape irregular
colour
Minor features:
diameter > 7mm inflammation oozing change
in sensation
Pigmented
lesions that show
changes should always be checked by an experienced doctor!
Treatment of melanoma
Melanoma (or
moles suspected
to be melanoma) are removed surgically. Thick melanomas require more
extensive
surgery than thin melanomas. Most countries have national guidelines
regarding
melanoma treatment procedures. For treatment details please consult
your national guidelines (United
Kingdom, Australia/NZ,
USA).
