Melanoma: An overview
Melanoma is usually a tumor of the skin though it can affect the other organs also. It starts in the melanocytes, these are the cells that produce the pigment melanin that colors the skin, eyes, hair, as well as forms moles. Since most of these pigment cells are found in the skin, melanoma of the skin is the most common melanoma. Among the various types of skin cancers, melanoma is the most serious type.
There are different types of Melanoma:
Cutaneous melanoma could be the
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Superficial Spreading Type
It accounts for 70% of melanomas. It occurs usually in a previously benign mole in the 4th to 5th decade of life. It is commonly found on the trunk and back in men and legs and back in women. It can present as a lesion with irregular borders, pigmentation, or as a focal area of darkening in a pre-existing naevus.
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Nodular Type
It accounts for 15% to 30% of newly diagnosed melanomas. It is very aggressive and the trunk is the common area involved.
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Acral Type
It accounts for 5% of all diagnosed melanomas but is more common in Asians and individuals with dark skin. Common sites are the sole, palm, and subungual regions.
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Lentigo Maligna
It is often mistaken for sunspots and accounts for 10% of all diagnosed melanomas occurring in the face of the elderly with sun damage. It occurs on the cheeks, nose, neck, and scalp. It presents as a slowly enlarging freckle-like patch with irregular shape and differing shades of tan or brown.
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Mucosal melanoma involves the mucosal surfaces including the nasal passages, throat, vagina, mouth, or anus. The ocular type involves the eye.
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Metastatic type indicates a stage where it has spread beyond the original site into the lymph nodes or other parts of the body.
Exposure to UV light from natural and artificial sources is the most important cause though along with environmental factors. Genetics and family history may be significant as it can also occur in areas not exposed to the sun as the mucosa. Periodic intense sun exposure rather than long-continued heavy exposure is considered riskier. Fair skin inability to tan, the tendency to sunburn, numerous moles, large congenital melanocytic naevi >20cm, and family history of melanoma are risk factors.
Melanoma Symptoms and Treatment
Symptoms
It can present as a change in the pigmented skin, a new spot or change in colour, shape, and size of a current spot, or an ulcer that does not heal. A mole that changes in size, shape, and color has irregular borders, which is more than 1 color, asymmetrical, which itches, bleeds, or is ulcerated, or develops new moles near the existing ones that need to be investigated.
Diagnosis is done using a biopsy or Fine-needle aspiration. The lymph nodes may also have to be mapped and subjected to biopsy X-rays, CT scans, MRI and PET scans, blood chemistry(LDH) should be ideally done for staging, which is essential for appropriate treatment. Immunohistochemistry may be done in poorly differentiated neoplasms.
Staging depends on
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The thickness of the tumor using the Breslow scale
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Whether the tumor has broken the skin
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Whether the tumor has spread to lymph nodes and if the lymph nodes are connected together (matted)
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Whether the tumor has spread to other areas or organs of the body
Types of Stages
Stage 0 (Melanoma in Situ)
The epidermis (outer layer of the skin) contains abnormal melanocytes that can spread into surrounding normal tissue.
Stage I Melanoma
In stage IA, the tumour is less than one millimeter thick, with no ulceration (break in the skin). In stage IB, the tumour is either less than 1 millimetre thick with ulceration, or more than 1 millimetre thick but not more than 2 millimetres thick with no ulceration. The thickness of the skin is different in different areas of the body.
Stage II Melanoma
- In stage IIA, the tumour is either more than 1 millimetre but less than 2 millimetres thick with ulceration (skin break) or more than 2 but less than 4 millimetres thick with no ulceration.
- In stage IIB, the tumour is more than 2 millimetres thick but not more than 4 millimetres thick with ulceration or it is more than 4 millimeters thick, with no ulceration.
- In stage IIC, the tumour is more than 4 millimetres thick and ulcerated. Skin thickness is different in different areas of the body.
Stage III Melanoma
The tumor may be of any thickness, with or without ulceration and (a) it has spread to one or more than one lymph node; (b) lymph nodes with tumor may be connected together (matted); (c) cancer may be in a lymph vessel between the primary tumor and nearby lymph nodes; and/or (d) very small tumors may be found on or under the skin, not more than 2 centimeters away from the primary tumor.
Stage IV Melanoma
The tumor spread to other parts of the body such as the lung, liver, brain, bone, soft tissue, and gastrointestinal tract.
In the early stages, the survival rate can exceed 90-95% but drops to 20% when it has spread.
Treatment
Simple excision, wide local excision, immunotherapy, interferon-alpha 2b, Interleukin 2, targeted treatment such as ipilimumab, and chemotherapy can be used. Radiotherapy may be needed for preventing a local recurrence of melanoma.
Poor Prognostic factors include more Tumour thickness, site, ulceration, and bleeding, elderly group, involvement of head and neck, spread to lymph nodes and other organs of the body, level of Lactic dehydrogenase.
Avoiding sun exposure in the peak hours, use of sunscreens with SPF(sun protection factor)at least 30, use of protective clothing, umbrellas hats, etc, and avoidance of tanning salons can help. Careful examination of all parts of the skin is important. If any change is noted in a mole, bleeding, itching, change in color, or size it should arouse suspicion. Self-examine for spots that are new, different, or changing.
Manipal Hospital is one of the best skincare hospital in Mangalore, we have some of the best Dermatologist in Mangalore who serve the skin health care needs of Mangalore and its surrounding areas in the state of Karnataka.
Dr. Maria Kuruvila Chacko
Consultant - Dermatology
Manipal Hospital, Mangalore
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