Cancer is one of the chief diseases affecting a majority of the population around the world. One of the more serious types of cancer of the skin is melanoma. This is the cancer that affects skin cells that produce the skin color or melanin, known as melanocytes. Though melanoma is termed as skin cancer, in some rare cases it can form in the eye or in internal organs, such as the intestines.



Types of Melanoma

Melanoma is categorized into four different types depending on where they occur. Of these four types, three occur in-situ or only on the top layer of the skin and are rarely invasive. One type is invasive right from the beginning and penetrates deep within the skin, thus taking a serious invasive form.

The four categories are

  • Superficial spreading melanoma—this is the most common and mostly seen in young adults. This type can occur anywhere on the skin and grows along the top layer of the skin before it penetrates deep within the skin.
  • Lentigo maligna—this type of melanoma is similar to the superficial spreading type, but commonly seen in older adults. This melanoma spreads similarly to the superficial spreading melanoma, but is found on sun-exposed surfaces. It is a common type of skin cancer in Hawaii.
  • Acral lentiginous melanoma—this type is more commonly seen in Asians and African Americans compared to Caucasians. This type of melanoma starts as a brown or black discoloration on the palms of the hand, soles of the feet, or under the nails and spreads superficially before penetrating deep into the skin. Owing to its symptoms, this kind of melanoma is detected much later compared to the other types.
  • Nodular melanoma—this most aggressive and malignant type of melanoma is found in the trunk of the leg and arms as well as the scalp of men, especially in the elderly population. It is penetrative and metastatic when detected itself. The melanoma is in the form of a bump, which is usually black, but the color might vary.



Symptoms of Melanoma

Melanoma can develop anywhere on the body, but is usually formed in the areas that are most exposed to the sun and its UV rays. In darker people (most often) melanoma can even develop in areas not exposed to the sun, such as the soles of the feet, fingernail beds, or palms.

The first visible symptoms of the disease are unusual growth on the skin, or new pigmentation on the skin and/or a change in the appearance of existing moles on the body.


Unusual moles can be identified by considering the following ABCDE:

A – asymmetrical moles or ones with irregular shapes

B – borders of moles are irregular with scalloped or notched borders

C – color of the moles has an uneven distribution or has several colors

D – diameter of moles, especially new moles that are one-fourth inch, is worrisome

E – moles that keep evolving, either growing in size or changing shape or color


Moles of melanoma usually display ABCDE characteristics.


Sometimes the moles can also be hidden, such as under a nail or in the mouth, vaginal area, urinary tract, or digestive tract. Melanoma can even be developed in the eye behind the white sclera.


Any irregular moles or patches must be checked and examined.