Skin cancer is the most common of all cancers. Melanoma causes most of the serious complications of skin cancer but accounts for less than 5% of all skin cancer cases. But just what is melanoma? And how is it different than other types of skin cancer?

Skin anatomy
Melanoma is a cancer that starts in a certain type of skin cell. To understand melanoma, it helps to know some things about normal skin. The skin is the largest organ in the body whose principle responsibilities are to:

• control body temperature
• cover the organs inside the body and protects them from injury
• keep in water and other fluids
• keep out germs

What is melanoma?
Melanoma is a cancer that begins in the melanocytes. Melanoma most often begins on the trunk or lower legs of fair-skinned people, but it can start in other places, too. The skin has 3 layers  listed here from least to most deep:

1. epidermis
2. dermis
3. subcutis

Melanocytes, cells that are found in the epidermis, are the cells that can become melanoma. These skin cells make the brown pigment called melanin which makes skin tan and protects the deeper layers of the skin from the harmful effects of the sun.

Types of melanoma

1. Superficial spreading melanoma (SSM) - This type of melanoma is the most commonly diagnosed. SSM is the leading cause of death from cancer in young adults. This melanoma can occur anywhere on the skin's surface.
2. Nodular melanoma (NM) - Nodular melanoma is the most aggressive and serious type of melanoma. NM can appear anywhere on the body. NM differs from other types of melanoma in that is tends to grow more rapidly in thickness than in diameter, may be visible during development and can appear in a location where skin lesions did not previously exist.
3. Lentigo maligna melanoma (LMM) - This type of melanoma occurs on sun-damaged skin of middle-aged and/or elderly people, especially on the face and is often mistaken for a benign "age spot" or "sun spot." LMM can be dangerous if it goes undetected for years.
4. Acral lentiginous melanoma (ALM) - ALM is the most common form of melanoma for people with dark skin and is sometimes referred to as a "hidden melanoma" because these lesions occur on parts of the body not easily examined or not thought necessary to examine. ALM develops on the palms, soles, mucous membranes (such as those that line the mouth, nose, and female genitals), and underneath or near fingernails and toenails.

Doctors can diagnose various types of melanomas, but still don't know what causes the condition.  You can, however, avoid certain risk factors that will make it less likely that you develop the condition.  Continue reading here for more information about risk factors and what might be the cause of melanoma here.