Melanoma in colored skin

What is it melanoma?

Melanoma is a form of skin. Cancer formed from uncontrolled growth and replication of melanocytes (pigment cells) [1]. Melanoma is sometimes known as evil one melanoma and has a variety of subtypes.

What is colored skin?

"Colored skin" is a subjective term used to refer to natural skin pigmentation "Darker" than white (ie, brown or black skin). When compared to a gradual evaluation of skin color, such as Fitzpatrick phototypes, colored skin can refer to skin classified as type IV or higher [2]. In some contexts, colored skin is also used to describe the skin of different non-white ethnic groups, including those of African, Asian, South American, Pacific Islander, Maori, Middle Eastern, and Hispanic descent. [3]. View ethnic dermatology.

Who gets melanoma?

Melanoma can develop on any skin type, but is most often seen in people with light-colored skin. Conversely, darker skin color is associated with a reduced risk of developing melanoma. [4]. This trend is evident when comparing the melanoma rates observed in various ethnic groups predisposed to different skin colors.

In the United States during the period from 1999 to 2006, of 288,741 patients with advanced melanoma [5]:

• 95% were white
• 0.5% were black
• 0.3% were Asian or Pacific Islander.

In New Zealand during the period from 1996 to 2006, of 16,425 newly registered melanoma cases [6]:

• 99% were in New Zealand Europeans
• 1% were in Maori
• 0.2% were on Pacific islands
• 0.1% were in Asians.

Skin color is an independent but significant risk factor for melanoma in various ethnic groups, and most cases are diagnosed at a median of 50 to 65 years of age. [5].

People with colored skin tend to have:

• Thicker melanomas at diagnosis and higher mortality rates [4,7]
• Significantly higher rates of melanomas in areas not exposed to the sun, including the subungual, palm and plant surfaces (eg acral Lentiginous melanoma in Pacific, Black and Asian islanders) [4,6,7]
• Not-cutaneous melanomas (eg. mucous membrane melanoma, ocular melanoma) [4–7].

People of all skin colors with a family history of melanoma have an increased risk of developing melanoma due to a genetic predisposition [8].

What causes melanoma?

Melanoma is due to uncontrolled proliferation of melanocytic stem cells following progressive genetic transformations [1,9,10].

In most cases, this genetic change is triggered by exposure to the sun. Ultraviolet (UV) radiation damages and mutates the DNA [9.10]. In dark skin, a higher content of UV radiation absorption. melanin it is protective [7,11,12], and the use of sunscreens is not required to protect them from melanoma.

Melanoma can also arise in areas not exposed to sunlight and in tissues other than the skin. The rates of these melanomas may be higher in non-white ethnic groups [13].

What are the clinical features of melanoma?

Melanoma can occur anywhere on the skin. On colored skin, melanoma often develops in places with low sun exposure, such as palms or soles (acral lentiginous melanoma) [5,6,14,15]. Less often, melanoma can occur in mucous membranes, such as the mouth or genitals, or other parts of the body, including the brain and eyes.

• At first, a melanoma may look like a freckle or mole and can itch or bleed.
• Colors for melanoma include tan, dark brown, black, blue, red, and occasionally light gray or a mix of those colors.
• Melanomas can grow through the skin (that is, in radius, known as the radial growth phase) or grow in depth (known as the vertical growth phase).

It can be more difficult to identify melanomas, their growth phase, and their pattern on colored skin, as the surrounding skin may mask or match the color of the melanoma. Characteristic features follow. Note: these features are not always present and do not always indicate malignant growth [1,4].

Glasgow's 7-point checklist

Main features

• Size change
• Irregular shape
• Irregular color

Minor features

• Diameter> 7mm
• Inflammation
• Oozing
• Change of feelings.

The ABCDE of melanoma.

• A: Asymmetry
• yes: Border irregularity
• C: Color variation
• re: Diameter> 6mm
• me: Evolving (expanding, changing).

Precursor injuries

Melanoma on colored skin can develop from normal skin or other skin lesions, including [1,16]:

• Congenital melanocytic naevi (brown or gray birthmarks) - especially large / giant melanocytic nevi
• Benign Melanocytic nevi (normal moles).

How is melanoma diagnosed?

The troubling skin lesions are compared to the person's other skin lesions. If they appear distinctive, they are often examined by dermoscopy to look for features that could not otherwise be identified with the naked eye. Diagnosing melanoma by visual inspection can be difficult, especially on colored skin where, as mentioned above, the surrounding skin can mask or match the color of the melanoma. [1,4].

Suspicious lesions are surgically removed to pathological examination (diagnosis excision) using a margin of 2–3 mm around the injury. Partial biopsies sometimes they are considered for larger suspicious lesions [1].

Pathological diagnosis of melanocytic lesions can also be difficult. The use of immunohistochemical stains can be considered to confirm whether a suspicious lesion is melanoma [1].

Which is the differential diagnosis for melanoma?

Differential diagnoses for melanoma include:

• Benign Melanocytic Nevi (moles)

• Basal cell carcinoma (the most common skin cancer in whites, Asians, and Hispanics) [4]
• Scaly cell carcinoma (the most common skin cancer in blacks and Indians) [4]
• Pigmented actinic keratosis
• Seborrheic keratosis
• Dermatofibroma
• Pyogenic granuloma
• Post-inflammatory hyperpigmentation

• Keloid scars

• Cutaneous metastasis.

Especially in colored skin, the following diagnoses should be considered as alternative diagnoses.

Naevi from special sites

Special site nevi are nevi that develop in atypical areas, including the genitals, breasts, palms, soles of the feet and flexural regions (armpits, elbows, back of knees). Although they are benign, they can show a histological melanoma-like structure. This diagnosis should be particularly considered in colored skin, since these nevi occur in places where melanoma commonly occurs in these skin types [5,6,11,14,15].

Post-inflammatory hyperpigmentation

Post-inflammatory hyperpigmentation is the darkening of the skin after inflammation; This is often more intense and persistent on colored skin, which can cause unnecessary distress and confusion in patients. [12].

Keloid scars

Keloid scar It is an elevated scar that grows beyond the limits of the original injury. Keloid scarring is more common on colored skin and may resemble a desmoplastic melanoma (which is very rare) [17–19].

What is the treatment for melanoma?

Confirmed melanoma generally undergoes a second surgical procedure known as wide local excision. The clinical margins of this excision are dependent on the size and thickness of melanoma [1]. The New Zealand recommended ranges for melanoma excision are as follows:

• Melanoma in the place: 5–10 mm
• Melanoma <1mm: 10mm
• Melanoma 1–2 mm: 10–20 mm
• Melanoma> 2 mm: 20 mm.

It is also important to determine the extent or "stage" of the melanoma and whether it has spread from the site of origin. The American Joint Committee on Cancer (AJCC) (2009) Staging Guidelines for Cutaneous Melanoma are the commonly used staging criteria. The AJCC staging criteria for cutaneous melanoma are as follows [20]:

• Stage 0: melanoma in situ
• Stage I: thin melanoma <2 mm thick
• Stage II: Thick melanoma> 2mm thick
• Stage III: Extended melanoma to involve local lymph nodes
• Stage IV: distant metastasis have been detected

Note: Non-cutaneous forms of melanoma may have different staging criteria [1,20].

Should the lymph nodes be removed?

If a melanoma spreads beyond its site of origin (becoming 'metastatic melanoma "), the surrounding lymph nodes may become enlarged. In such cases, the lymph nodes must be surgically removed under a anesthetic [1].

Normal, non-enlarged lymph nodes can also be analyzed to identify microscopic melanoma spread; this test is called the sentinel node biopsy and can help in staging cancer [1].

Systemic therapy

Systemic therapies may be offered in cases of advanced melanoma or metastatic melanoma (stages AJCC IIB, IIC, and IIIC) [21].

Immunotherapy

Immunotherapy involves the use of drugs that stimulate the body's immune system to act against melanoma cells; It may include:

• Inactive melanoma cells, which can be used to form experimental vaccines.

• Therapy with interferon α-2b as a assistant therapy [21,22]

• the cytotoxic T-lymphocyteipilimumab, antagonist of associated protein 4 (CTLA-4)
• Programmed blockade of cell death protein 1 (PD-1) antibodies [23–26] nivolumab and pembrolizumab.

Chemotherapy

Chemotherapy drugs for melanomas have shown limited success in treating melanoma and are not believed to improve overall survival. [twenty-one]. They include:

• Dacarbazine
• Photemustine
• Temozolomide

Targeted therapy

Targeted therapy medications are offered to patients with advanced or non-operable melanomas who express mutations [21].

Targeted melanoma chemotherapies available in New Zealand include [27–32]:

• BRAF inhibitors: dabrafenib and vemurafenib
• MEK inhibitors: trametinib
• BRAF / combinationMEK inhibitor: Cobimetinib
• C-KIT inhibitors: imatinib, nilotinib
• PD-1 blocking antibodies: nivolumab, pembrolizumab.

Radiotherapy

Radiation therapy can be administered for several weeks in the treatment of persistent melanomas or melanomas unsuitable for excision. In metastatic melanoma, radiation therapy can be used to relieve symptoms associated with metastases. [21.33].

What is the result for melanoma?

the forecast Melanoma on colored skin may be poorer overall compared to melanoma on white skin. This could be due to late presentation or detection leading to thicker melanomas or more aggressive melanoma subtypes. [4-8]. Regardless of skin color, the prognosis generally depends on the AJCC stage of melanoma, the level of Clark's invasion, and Breslow thickness at the time of the excision of the primary injury [1].

The 5-year survival rates (%) according to the simplified AJCC staging classification [34] are as follows:

• Stage I: 90–95%
• Stage II: 45–78%
• Stage III: 26–66%
• Stage IV: 7.5–11%.

5-year survival rates in different tumor Table 1 shows the depths for the different ethnic groups of 17 cancer registries based on the US population in the period from 1999 to 2005 [5].