Melanoma can occur on a pre-existing nevus (mole) but it can also occur de novo, i.e. in an area that was previously healthy. It occurs more often in areas with chronic sun exposure, but it can also occur in non-exposed areas such as the palms, the soles and the perineum.
The risk factors for the development of melanoma are:
People with light skin pigmentation (phototype Ι)
Presence of many nevi (moles) on the skin > 50 or presence of dysplastic nevi (deformed nevi)
Presence of congenital nevus
History of malignant melanoma in the family
Many lentigines or freckles on the skin of the face, hands and body
Intense intermittent exposure to the sun (e.g., in the summer)
History of sunburn during childhood
Intense exposure to artificial UV radiation sources e.g., solarium
What does melanoma look like?
Melanoma usually resembles a nevus or freckle but with a different, from the usual, morphology. The color can vary from black, blue, dark brown or gray. In more advanced lesions, the melanoma may begin to enlarge and become thicker. Symptoms such as pruritus (itching), bleeding and crusting may coexist.
Prognosis of patients with melanoma
If melanoma is early diagnosed, its prognosis may be good and treatment can lead to complete cure. The superficial spreading melanoma and the nodular melanoma are the most aggressive types of melanoma. Early diagnosis of small superficial lesions can lead to complete cure, while advanced tumors with occurrence of metastases may limit the mean survival time to 6‑9 months.
Clinically suspected signs of melanoma:
Change of shape, color and size of a lesion
Asymmetry or border irregularity
Bleeding or crust formation
Change of color or many colors within a nevus
Area diameter greater than six millimeters
Raised area on a previously flat nevus
Ulceration and pruritus (itching) may indicate malignant transformation
Due to the aggressiveness and rapid growth of the tumor, it is very important to detect melanoma as soon as possible.
Since it is difficult for the patient himself to identify suspicious lesions, it is imperative for a qualified dermatologist to examine the nevi (moles) at least once a year. The dermatologist will determine whether dermoscopy and mapping of nevi is required, in order to allow detailed monitoring.
A positive biopsy is followed by an additional wider surgical excision of the tumor, lymph node examination (sentinel node) and staging of the tumor.
In some cases radiotherapy and chemotherapy may be required.
If melanoma is diagnosed early it can be cured completely.