Acral Melanoma Dermoscopy

Acral melanoma is a special subtype of skin cancer. Late presentation of patients and delayed diagnosis by doctors result in poor prognosis and survival. Despite advances in the understanding of the key features of this disease, early diagnosis of acral melanoma remains challenging. A combination of clinical presentation, dermoscopy, and histologic findings is essential for the diagnosis of acral melanoma.

What is acral melanoma?
Acral melanoma is also known as acral lentiginous melanoma. Acral melanoma is a rare subtype of melanoma. And it usually happens in acral of the body, like palms on the hands, soles of the feet, and under the nails. Unlike other melanomas that is usually caused by over sun exposure and occurs in fair-skinned people . Oppositely, the places include palms, soles and under the nails are not commonly exposed on sunburn. Dark people usually don’t get melanomas. However, acral melanoma is the most common type of melanoma in dark people and it also affect people of all ethnic backgrounds. Hence these these melanomas are found later than other types of melanomas after they invade deeper layers of the skin or metastasize. So it brings more difficult to detect and diagnose the acral melanoma than other skin cancers.

What are the difficulties in diagnosing acral melanoma?
As the acral melanoma is usually found late by patients, there are some difficulties and misunderstandings in the diagnosing acral melanoma as below:
Atypical Presentation: Early acral melanoma lesions are often difficult to diagnose because the pigmentation of the lesions usually follow the skin marking on the palms and soles, resulting in asymmetrical appearance and irregular borders. This similarity with benign melanocytic moles can make early diagnosis difficult.
Misconceptions: There is a misconception that melanoma only happen on the areas exposure in sun. So people always will neglect the changes on other parts of the skin, which causes the delayed diagnosis of acral melanoma.Unfortunately, this will lead to acral melanoma being found at advanced stage and bring a poor treatment effectiveness.
Histopathological complexity: The biopsy and histopathological examination needed to diagnose acral melanoma may be very complexity. Because acral melanoma cells may not present its typical characteristics always. This lead to a potential misdiagnosis.

Advantages of dermoscopy in the diagnosis of acral melanoma
To improve the diagnosis of acral melanoma, it is crucial to use the advanced diagnosis technique dermoscopy. Dermoscopy is a handheld device equipped with a magnifying lens and a light source to allows a enhanced visual for dermatologist to diagnose skin lesions and skin conditions, like acral melanoma and other types of skin cancer. In professional hands, dermatoscope can help to diagnose the very early stage of melanoma by typical structures and patterns which can not visual by naked eyes. In addition, the dermatology is invasive and painless. It not only can avoid the cross infection during examination but also can reduce the unnecessary biopsy and surgery.
Some modern advanced dermoscopes can capture image of lesion or connect to computer software for better analysis.

What are dermoscopic features of acral melanoma?
Dermoscopy is an essential tool to help dermatologists diagnose the acral melanoma by providing critical visual clues that differentiate it from benign lesions. There are some key dermoscopic features associated with acral melanoma as below:
Parallel Ridge Pattern: This pattern is characterized by irregular and disrupted pattern that follows the ridges of the skin on the palms and soles.
Irregular Diffuse Pigmentation: Uneven distribution of pigmentation color, often with multiple shades of colors.
Multiple or Mixed Colors: Acral melanoma lesions often present a mix of brown, blue-grey, black, and red colors or multiple colors.
Irregular Dots and Globules: Exhibit of scattered dots and globules of varying size and colors within the lesion.
Atypical Vascular Patterns: Presence of unusual or irregular blood vessels within the lesion.
Asymmetrical and Irregular Border: Acral melanoma with asymmetrical structures and irregular, uneven,notched or blurred borders.

Distinguish the dermoscopic features of similar lesions like acral nevus
Acral nevus (benign melanocytic nevus) and acral melanoma may present similar characteristics. While dermoscopy is a very important and necessary tool tell the differences from them. Here are the key points for distinguishing acral nevus from acral melanoma including:

Exploring the factors affecting the prognosis of acral melanoma
Due to the late inspection and detection of acral melanoma, resulting in a poor prognosis. Except for that, there are some other factors that affect the prognosis of acral melanoma as below:
Feature of the lesion :
Size and Location: If the size of the lesion Larger than 4 mm, and those also located in weight-bearing areas like the soles or under the nails can be more challenging to detect and treat early. This means a potentially worsening prognosis.
Ulceration: Commonly ulcerated lesions are associated with a worse prognosis than the one is not ulcerated.
Thickness: Thickness is the obvious factors which affect the prognosis of acral melanoma. The thicker tumors (greater breslow depth) are often associated with a more worse prognosis.
Stage of the Lesion:
Advanced Stages: Patients diagnosed at advanced stages that means the lesion have invaded into lymph nodes or other parts of the body have a poor prognosis. Advanced stage brings more difficulties in survival rate.
Age and Gender: As reported and analysis, that the older age and the male patients generally tend to have poor prognosis than the young and the female.
Gene mutation :
Commonly gene mutation such as BRAF, KIT, NRAS,and so on, this altered genes can influence prognosis and response to targeted therapies. It causes a poor prognosis of acral melanoma.
Immune System: Especially the patients diagnosed at acral melanoma or other cancers and with low immune system tend to have a worse prognosis than the normal ones.

How to improve the diagnosis of acral melanoma?
As we know that it is difficult to detect and diagnose the acral melanoma especially in its early stage due to its special characteristics. Then how to improve the diagnosis of acral melanoma? There are some methods to improve the diagnosis of acral melanoma including:
People should raise the awareness about the possibility of melanoma in non-sun exposed areas and learn more knowledge about this rare and special skin cancer.
People should do more regular self-examinations by dermoscope, especially of the palms, soles of the feet, and under of nail if there is unusual spots or dots.
People and dermatologists should use dermoscopy, an advanced diagnostic device and techniques to inspect skin situations. Particularly, it is a must to have skin checked by dermoscopy by professional doctors when suspicious lesions are found.

As we can see, early detection are very important to improve the prognosis of acral melanoma. Dermoscope indeed plays a vita role in detecting, diagnosing, monitoring and managing skin lesions and skin cancers like acral melanoma. Dermoscopy is a very valuable and helpful device in the field of dermatology, significantly increasing the ability to inspect and diagnose acral melanoma in early stage. Dermoscopy not only improves patient confidence through early intervention and appropriate treatment schedule, dermoscopy but also reduce the infection during the examination.