Skin Cancer
Recognition of skin cancers:
Melanomas, SCC, BCC, Bowens and other skin cancers.
Other lesions
Solar keratoses, blue naevus, seborrhoeic keratoses,
Discussion of major types
1. BCC
Basal cell carcinoma:
Basal cell carcinoma
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the most common and least dangerous form of skin cancer
appears red, pale or pearly in colour
appears as a lump or dry, scaly area
may ulcerate or fail to completely heal
grows slowly, usually on the head, neck and upper torso.
This flesh-colored, verrucal, pearly, smooth, non-scaling papule is
a basal cell carcinoma. It is occurring in a common, sun-exposed
area of the face, on the forehead.
This skin cancer, a basal cell carcinoma, is 5 to 6 centimeters
across, red (erythematous), with well defined (demarcated)
borders and sprinkled brown pigment along the margins. This
cancer is located on the person's back.
The typical basal cell skin cancer appears as a small, pearly,
dome-shaped nodule with small visible blood vessels
(telangiectasias).
This skin cancer appears as a 2 to 3 centimeter skin spot. The
tissue has become destroyed (forming an atrophic plaque). There
is a brownish color because of increased skin pigment
(hyperpigmentation) and a slightly elevated, rolled, pearl-colored
margin. This growth is located along the hair line.
2 SCC
Squamous cell carcinoma:
Squamous cell carcinoma
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not as dangerous as melanoma
appears as a thickened, red, scaly spot that may bleed easily, crust or
ulcerate
appears on skin most often exposed to the sun
grows over some months
more likely to occur in people over fifty years.
Metastasis common
3. Melanoma
Melanoma is cancer of the skin's melanocytes (pigment cells) and the most
deadly form of skin cancer. If untreated, it can spread to other parts of the
body. There are two main types of melanoma.
Melanoma
a) Common (or superficial spreading) melanoma:
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appears as a new spot or an existing spot that changes colour, size or
shape
has an uneven, smudgy outline and is an irregular mix of colours
may appear on skin not normally exposed to the sun.
b) Nodular melanoma is not as common. It:
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grows quickly
looks different from common melanomas - is raised from the start and
even in colour
may be red or pink; some are brown or black
is firm to the touch and dome-shaped
will begin to bleed and crust, after a while.
Nodular melanoma
c) acral lentiginous melanoma
also known as subungual melanoma. It is seen on the palms, soles and under
the nails. This is the most common form of melanoma in Asians and Blacks.
The average age at diagnosis is between sixty and seventy years. It also
occurs in Caucasians and in young people. This type of melanoma occurs on
non hair baring surfaces of the body which may or may not be exposed to
sunlight.
Typical symptoms include:
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longitudinal tan, black, or brown streak on a
finger or toe nail (melanonychia striata)
 pigmentation of proximal nail fold
 areas of dark pigmentation on palms of
hands or soles of feet
Any new area of pigmentation or an existing one that shows change should
be checked by a dermatologist. If caught early this type of melanoma has a
similar cure rate as the other types of superficial spreading melanoma.
d) lentigo maligna (melanoma)
Lentigo maligna is a melanoma in situ: it consists of malignant
cells but does not show invasive growth. It can remain in this non-
invasive form for years. It is normally found in the elderly (peak
incidence in the 9th decade), on skin areas with high levels of sun
exposure (for example, face and forearms). When it develops into
melanoma, the resulting lesion is called lentigo maligna
melanoma. The transition to melanoma is marked by the
appearance of a bumpy surface (vertical growth, invasion). Therapy
of lentigo maligna consists of surgical excision (best) or
radiotherapy (only in special cases).
Lentigo maligna melanoma
Any of the above types may produce melanin (and be dark in colour) or not
(and be amelanotic - not dark). Similarly any subtype may show desmoplasia
(dense fibrous reaction with neurotropism) which is a marker of aggressive
behaviour and a tendency to local recurrence.
Popular method for remembering the signs and symptoms of melanoma is the
mnemonic "ABCDE":
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Asymmetrical skin lesion.
Border of the lesion is irregular.
Color: melanomas usually have multiple
colors.
 Diameter: moles greater than 5 mm are
more likely to be melanomas than smaller
moles.
 Evolution: The evolution (ie change) of a
mole or lesion may be a hint that the lesion
is becoming malignant --or-- Elevation: The
mole is raised or elevated above the skin.
Early melanoma
Level 3 Melanoma
Level 4 Melanoma
Breslow's depth is most accurately measured by evaluating the entire tumor
via an excisional biopsy. Determination from specimens obtained using other
biopsy techniques, such as a wedge or punch biopsy, are less accurate.
Breslow's depth should never be calculated from a shave biopsy; these
specimens contain only a portion of the tumor and can easily lead to an
underestimation of its thickness.
Clark's levels is a related staging system, often used in conjunction with
Breslow's depth, which depends on multiple anatomical landmarks in the skin.
In fact, Clark's level was the primary factor in earlier AJCC staging schemae
for melanoma. However, with further study, it has been shown that Clark's
level has a lower predictive value, is less reproducible, and is more operatordependent as compared with Breslow's depth. Thus, in the current (2002)
AJCC staging system, Clark's level has prognostic significance only in
patients with very thin (Breslow depth <1 mm) melanomas.
Solar keratoses or sunspots:
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a warning sign you are prone to sun damage and skin cancer
appear as red, flattish, scaling dry skin that may sting if scratched
appear on areas of skin most often exposed to the sun, like hands and
face
are most common in people over forty years
Solar keratosis
Seborrhoeic keratoses:
Seborrhoeic keratoses
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spots with a clear edge; they look like they sit on top of the skin
most people have at least one or two of these spots by the age of sixty
vary in colour from pale brown to orange or black
vary in size from a few millimetres to 2 cm.
Cutaneous Markers of internal malignancy
See http://www.dermnetnz.org/systemic/malignancy.html
Atypical Naevus
Atypical naevi can be considered funny looking moles.
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They may be larger than average (5-15mm)
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They may be an unusual shape or have a notched or blurred border.
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The colour is variable and may be pink, brown or black.
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The surface may be bumpy or smooth.
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They have characteristic dermoscopic features.
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They may have atypical or dysplastic features on biopsy.
Blue Naevus
Halo Mole