What is melanoma?

1. What is melanoma?

The term melanoma implies a malignant tumor; malignant melanoma is redundant. The most malignant of all skin cancers, melanoma usually forms from a preexisting nevus or mole but may develop de novo.

2. What is the incidence of melanoma?

It is the sixth most common cancer in the United States and the fastest rising cancer in men. The lifetime risk in the year 2000 was 1 in 75 versus 1 in 150 in 1985. Over 51,000 new cases of melanoma are reported each year.

3. What are the types of moles? Which are most prone to malignant change?

Intradermal: the most benign form
Junctional: the junctional component may be the site of melanoma formation
Compound: intradermal and junctional together; intermediate activity
Spitz: once called juvenile melanoma, it is actually a spindle cell epithelioid nevus that is quite benign
Dysplastic: the most likely to turn malignant (especially in dysplastic nevus syndrome)

4. What are the risk factors in melanoma formation?

Large number of moles (> 50 moles > 2 mm in diameter)
Changing nevi
Family history of melanoma
Light, poorly tanning skin; blonde or reddish-brown hair
History of episodic, acute, severe sunburns
Dysplastic nevus syndrome, or familial atypical multiple mole melanoma syndrome (FAMMM)
History of melanoma

5. Which skin lesions often mimic a primary melanoma?

Spitz nevus (spindle cell epithelioid nevus)
Atypical benign nevus
Halo nevus
Recurrent benign nevus after inadequate excision
Metastatic melanoma to skin
Mycosis fungoides
Extramammary Paget's disease
Bowen's disease
Dark sebaceous keratoses
Kaposi's sarcoma
Pigmented basal cell carcinoma

6. What is the familial melanoma syndrome?

The inherited FAMMM syndrome has been defined as the occurrence of melanoma in one or more first- or second-degree relatives and the presence of > 50 moles of variable size, some of which are atypical histologically. The risk of melanoma in this syndrome runs as high as 100% in the person's lifetime.

7. Is a specific gene involved in melanoma development in the FAMMM syndrome?

Genetic studies have revealed a specific gene (i.e., p16 mapped to chromosome 9) in many people with the FAMMM syndrome.