Malignant Melanoma of the skin • Dr Gerard Ee

A darker side to our moles

Moles, whether cosmetically appealing or not, are what makes our appearances unique. In fact, these dark spots on our skin are, to some, integral to their identity. What is less known about moles, however, is how they develop. Interestingly, our moles develop from melanocytes, which are pigment-producing cells located in the most superficial layer of our skin, the epidermis. The pigment produced is called melanin, and this is what gives our skin its characteristic colour. When there is an accumulation of melanin at a particular area of our skin, this spot then assumes a darker colour than its surroundings, and forms what we know as a mole.
There is, however, an even darker side to our moles especially if they have an abnormal appearance. Unusual looking moles may be a cause for concern, as they may very well be an indication of skin cancer. This article endeavours to raise awareness of a type of skin cancer – the Malignant Melanoma – and its insidious association with abnormal looking moles.

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A darker side to our moles

LET'S TALK

An introduction to Malignant Melanoma

Skin cancer may be broadly categorized as melanomas or non-melanomas. While both are malignant cancers, melanomas tend to be more aggressive, and have a higher inclination to spread to other parts of the body as compared to non-melanomas. As its name suggests, Malignant Melanoma falls under the category of melanoma skin cancer. Contrary to non-melanomas which predominantly affect people of the older age group, the likelihood of developing melanomas is higher in women under 40 years of age. Although Malignant Melanoma is ranked as the least commonly occurring skin cancer, its numbers have been consistently rising worldwide. In fact, it is reportedly the most lethal form of skin cancer that one can get.
Malignant Melanomas occur when the melanocytes of the skin face some form of damage to its DNA. Subsequently, essential cell-signalling processes which tightly control the growth of these cells go haywire. As a result, the melanocytes proliferate uncontrollably, till a point where a cancerous lesion appears on the skin surface. The process in which melanocytes develop into melanoma cells – termed as melanogenesis – is believed to be due to an interaction of various genetic and environmental risk factors.

Who should be wary of getting Malignant Melanoma?

Some factors that increase one’s risk of getting Malignant Melanoma include exposure to ultraviolet radiation, positive family history of skin cancer, presence of excessive moles, history of sunburns and being under immunosuppressive therapy. Studies have shown that sporadic but intense exposure to ultraviolet radiation increases the risk of developing Malignant Melanomas more than consistent and long-term exposure. Additionally, while fair skin is another contributing factor for the development of Malignant Melanomas, darker-skinned people are still at risk of developing a more pernicious Malignant Melanoma on the less sun-exposed areas of their skin.

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How does Malignant Melanoma present itself?

Malignant Melanomas can present itself on any area of our skin. In fact, their external manifestation varies according to their clinical subtype. Broadly speaking, Malignant Melanomas can be grouped into four main clinical subtypes: superficial spreading melanoma (SSMM), lentigo maligna melanoma, nodular melanoma and acral lentiginous melanoma. SSMM is the commonest out of the four clinical subtypes and tends to appear as an abnormal looking mole. Lentigo maligna melanoma, on the other hand, is less common, has a slow growth, and is associated with sun-exposed areas of the skin. As for nodular melanomas, while they grow rapidly, it is difficult to diagnose them early because they are not pigmented. Lastly, acral lentiginous melanoma is associated with darker skin people and tends to appear on the less sun exposed areas of the skin.

How is Malignant Melanoma diagnosed?

As Malignant Melanomas have a high potential of spreading to other parts of the body, it is crucial to seek prompt diagnoses! Having read the aforementioned presentations of Malignant Melanomas, the sighting of an unusual looking mole or any other suspicious skin changes should raise alarm bells for skin cancer. It is important to seek proper consultation with a relevant medical professional to confirm the diagnosis.

Usually, the process involves taking into consideration the patient’s medical history, a physical examination and some laboratory tests. When investigating the patient’s medical history, relevant questions surrounding the suspicious skin lesion will be brought up. In addition, the patient will be asked if they have had skin cancer or any type of cancer before, as well as their knowledge of any family member who has/had cancer.

As for the physical examination, the doctor will be observing the suspicious skin lesion(s) and other parts of the body to look out for any incidental and significant skin changes. In fact, two important risk factors the doctor will be looking out for include fair skin and the presence of excessive moles. Should the suspicious skin lesion be a mole, it is vital to take into account some of its key characteristics such as: presence of asymmetry, the border, colour, diameter and evolution. In addition to this assessment, the doctor can also utilise the Glasgow 7-point checklist to assess the patient’s risk of skin cancer.

Followed by this, the doctor typically recommends doing a skin biopsy of the suspicious lesion in order to test if this lesion is cancerous, and to also reveal the type and subtype of skin cancer. Apart from doing a skin biopsy, doing a biopsy of the patient’s lymph nodes is also important if the doctor suspects that the cancer has spread.

What are the treatments available for Malignant Melanoma?

While a timely diagnosis of Malignant Melanoma is important, seeking early treatment for this skin cancer is equally vital. When deciding on the course of action for a patient, there is a need to take into account the size and stage of the cancerous lesion, as well as the overall health and personal preference of the patient.

Early stage Malignant Melanomas tend to be treated with surgical excision. This process involves removing both the cancerous lesion and a margin of healthy tissue surrounding it to ensure complete removal of the cancer cells. Should the Malignant Melanoma have spread to other parts of the body, surgical excision must be performed for not only the cancerous lesion but for the affected lymph nodes too. Furthermore, such a patient will need to undergo other forms of adjuvant therapy such as radiation therapy and chemotherapy. Drugs are also available to target certain cancer cells or strengthen one’s immunity to counter the cancer. Examples of such drugs include iplimumab, nivolumab and trametinib.

When the Malignant Melanoma is in its late stage, the prognosis of the patient is poor even with relevant treatment given. This only emphasizes the critical importance of detecting suspicious skin lesions and receiving treatment early.

Conclusion

With the incidence of Malignant Melanoma on the rise worldwide, coupled along with its devastating lethal effects, there is a considerable burden placed on healthcare services. In order to prevent these numbers from increasing any further, there are a few ways that one can take to reduce their risk of developing Malignant Melanomas. Some of them include minimising exposure to the sun, using sunscreen in order to protect oneself from ultraviolet radiation, as well as being more observant of unusual skin changes. It is wise to bring up any suspicious skin changes to a relevant medical professional and seek treatment for it promptly.