Acral lentiginous melanoma (ALM) is a rare form of skin cancer. It accounts for only two or three percent of all melanomas. It appears on the palms, soles of the feet, toes or fingers. It usually appears as a flat discoloration but as the cancer progresses it becomes thicker. It follows the ABCDE rule of cancer: asymmetry, border irregularity, color variation, large diameter and evolving. This is the type of cancer that killed Bob Marley.
A recent study, published in the journal Pigment Cell & Melanoma Research in August, 2014, showed that this type of melanoma is not caused by sun exposure. Researchers compared the DNA damage in eight patients with acral melanoma with those of other types of skin cancer. They found that in ALM, it was more common to have large pieces of DNA break off and then reattach somewhere else. In other forms of melanoma, scientists saw smaller DNA changes. Their research showed that the DNA damage caused by ALM was not caused by UV damage.
Identifying Acral Lentiginous Melanoma
In the early stages, ALM looks like a patch of discolored skin. As the cancer develops, the lesion can become dry and warty. There is usually a mixture of colors within the lesion: brown, blue-grey, black and red. Less often it is mainly red in color. The lesion can become ulcerated and bleed.
As with other skin cancers, lesions from ALM are not symmetrical, have an irregular border, vary in color and change and evolve with time. The lesions are most often found on the palms of hands, the soles of feet or below the nail.
The early stage of ALM can last for months or years. During this stage, the cancer cells stay in the epidermis. As it progresses, the cancer cells cross into the dermis and from there can spread to other parts of the body. It can spread to the lymph nodes.
The first course of treatment is to surgically remove the lesion. Depending on the size, location and depth of the tumor, this can sometimes mean a partial amputation of a finger or toe. Once the tumor is excised, further treatment is usually based on the thickness. Tumors that are more than 2 mm are considered Stage 2. If the cancer has reached the lymph nodes, it is considered Stage 3 and if the cancer has spread past the lymph nodes to other areas of the body (metastatized), it is considered Stage 4 cancer.
Additional treatment can include immunotherapy and BRAF inhibitors. These types of treatments are not always successful. As with other types of skin cancer, early detection and treatment is important.
The recent study provides information on DNA changes from ALM. The scientists hope a better understanding of how the DNA is damaged will help develop targeted treatments for this rare type of skin cancer.
“Acral Lentiginous Melanoma,” 2009, Porcia T. Bradford et al, JAMA Dermatology, Vol 145, No 4
Published On: September 01, 2014