What is melanoma？
Melanoma is a malignant tumor that originates in melanocytes, pigmented areas of the skin, mucous membranes, eyes, and central nervous system.
Every year, 25,000 new cases of melanoma occur in the United States, and about 6,000 people die. Sun exposure is a risk factor, as is family history.
The types of melanomas
All melanomas consist of only one type of malignant cell, a malignant pigment-producing cell called a melanocyte, but they differ slightly in their morphology, such as spindle or cylindrical.
In skin melanomas, each type has a similar morphology. All melanocytes contain small granules of pigment, even when their cells are not black or dark brown.
When melanomas spread, they usually do not produce melanin and are therefore called apigmented. However, apigmented and pigmented melanomas are almost equally aggressive.
Where melanoma occurs
Melanomas most commonly occur in the skin, but 10% occur in the eye. The most common types in the skin are called superficial spreading melanoma and nodular melanoma.
Malignant melanoma can occur in unusual locations, such as under the nails of a finger or toe, or on the lining of the mouth, vagina, or anus. Primary malignant melanomas are also found in the pigmented tissue covering the brain (meninges).
It is important not to confuse malignant melanoma under the nail with a fungal infection, although this mistake is sometimes made in the early stages of the disease.