Superficial spreading melanoma (SSM) is usually characterized as the most common form of cutaneous
melanoma
Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...
in Caucasians. The average age at diagnosis is in the fifth decade, and it tends to occur on sun-exposed skin, especially on the backs of males and lower limbs of females.
Signs and symptoms
Often, this disease evolves from a precursor lesion, usually a
dysplastic nevus
A dysplastic nevus or atypical mole is a nevus (mole) whose appearance is different from that of common moles. In 1992, the NIH recommended that the term "dysplastic nevus" be avoided in favor of the term "atypical mole". An atypical mole may also ...
. Otherwise it arises in previously normal skin. A prolonged radial growth phase, where the lesion remains thin, may eventually be followed by a vertical growth phase where the lesion becomes thick and nodular. As the risk of spread varies with the thickness, early SSM is more frequently cured than late nodular melanoma.
Histopathology
The microscopic hallmarks are:
* Large melanocytic cells with nest formation along the
dermo-epidermal junction.
* Invasion of the upper epidermis in a
pagetoid
Pagetoid is a term used in dermatology to refer to "upward spreading" of abnormal cells in the epidermis (ie from bottom to top). It is uncommon and a possible indication of a precancerous or cancerous condition. Cells display pagetoid growth when ...
fashion (discohesive single cell growth).
* The pattern of rete ridges is often effaced.
* Invasion of the dermis by atypical, pleomorphic melanocytes
* Absence of the 'maturation' typical of naevus cells
* Mitoses
Treatment
Treatment is by excisional biopsy,
wide local excision
A wide local excision (WLE) is a surgical procedure to remove a small area of diseased or problematic tissue with a margin of normal tissue. This procedure is commonly performed on the breast and to skin lesions, but can be used on any area of the ...
and possibly
sentinel node biopsy. Localized melanoma, which has not spread beyond the skin, has a very good prognosis with low recurrence rates. Spread of disease to local lymph nodes or distant sites (typically brain, bone, skin and lung) marks a decidedly poor prognosis.
See also
*
Melanoma
Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...
*
List of cutaneous conditions
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against t ...
References
External links
Fact File from the Royal College of Pathologists of Australasia (pdf)
{{DEFAULTSORT:Superficial Spreading Melanoma
Melanoma