Malignant melanoma
Malignant melanoma is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. In women, they most commonly occur on the legs, while in men, they most commonly occur on the back. About 25% of melanomas develop from nevus. Changes in a nevi that can indicate melanoma include an increase in size, irregular edges, change in color, or ulcer.

The primary cause of melanoma is ultraviolet light exposure in those with low levels of the skin pigment melanin (white population). The UV light may be from the sun or tanning devices. Those with many nevus, a melanoma history of family members, and poor immune function are at greater risk at melanoma.

Using sunscreen and avoiding UV light may prevent melanoma. Treatment is typically removal by surgery. In those with slightly larger cancers, nearby lymph nodes may be tested for spread (metastasis). Most people are cured if metastasis has not occurred. For those in whom melanoma has spread, immunotherapy, biologic therapy, radiation therapy, or chemotherapy may improve survival. With treatment, the five-year survival rates in the United States are 99% among those with localized disease, 65% when the disease has spread to lymph nodes, and 25% among those with distant spread.

Melanoma is the most dangerous type of skin cancer. Australia and New Zealand have the highest rates of melanoma in the world. High rates of melanoma also occur in Northern Europe and North America. Melanoma occurs much less in Asia, Africa, and Latin America. In the United States, melanoma occurs about 1.6 times more often in men than women.

Signs and symptoms
Early signs of melanoma are changes to the shape or color of existing nevus. In the case of nodular melanoma, it is the appearance of a new lump on the skin. At later stages of melanoma, the nevi may itch, ulcerate, or bleed.

[A-Asymmetry] Asymmetry of shape
[B-Borders] Border (irregular with edges and corners)
[C-Color] Color (variegated and irregular)
[D-Diameter] Diameter (greater than 6 mm = 0.24 inch = about the size of a pencil eraser)
[E-Evolving] Evolve over time

cf) Seborrheic keratosis may meet some or all of the ABCD criteria, and can lead to false alarms.

Metastasis of early melanoma is possible, but relatively rare; less than a fifth of melanomas diagnosed early become metastatic. Brain metastases are common in patients with metastatic melanoma. Metastatic melanoma can also spread to the liver, bones, abdomen, or distant lymph nodes.

Looking at the area in question is the most common method of suspecting a melanoma. Nevus that are irregular in color or shape are typically treated as candidates of melanoma.
Physicians typically examine all moles, including those less than 6 mm in diameter. When used by trained specialists, dermoscopy is more helpful to identify malignant lesions than use of the naked eye alone. Diagnosis is by biopsy of any skin lesion that has signs of being potentially cancerous.

#Mohs surgery

Your doctor may recommend immunotherapy especially if you have stage 3 or stage 4 melanoma that can’t be removed with surgery.
#Ipilimumab [Yervoy]
#Pembrolizumab [Keytruda]
#Nivolumab [Opdivo]
  • A melanoma of approximately 2.5cm (1 inch) by 1.5cm (0.6 inch)
  • Malignant Melanoma ― right medial thigh. Seborrheic keratosis can be considered as a differential diagnosis.
  • Malignant Melanoma in situ ― Anterior Shoulder. Although the shape of the lesion is asymmetric, it is well defined with even color. In Asians, these lesion mostly present as benign lentigo, but a biopsy should be required in Western populations.
  • Malignant Melanoma ― Back lesion. In Asians, it is mostly diagnosed as lentigo, but a biopsy should be performed in Westerners.
  • Large acral lentiginous melanoma ― In Asians, acral melanoma on the palm and sole is common, whereas in Westerners, melanoma in sun-exposed areas is more common.
  • The soft black plaque surrounding the lesion is a common finding in acral melanoma.
  • The black spot that has invaded the nail matrix area outside the nail suggests malignancy.
  • Amelanotic melanoma under the nail is a rare occurrence. For elderly individuals with irregular nail deformities, a biopsy may be considered to check for both melanoma and squamous cell carcinoma.
  • Nodular melanoma
  • Amelanotic Melanoma ― Posterior thigh. Fair-skinned individuals often have the lesion of lightly pigmented or amelanotic melanomas. This case does not show easily observable color changes or variations.
  • Scalp ― In Asians, such cases are commonly diagnosed as benign lentigo (not melanoma). However, large pigmented patches on sun-exposed areas require biopsy in Western populations.
  • Malignant Melanoma ― forearm. The lesion exhibits an asymmetric shape and irregular border.
  • Malignant Melanoma in situ ― Forearm.
  • Malignant melanoma on the mid back. The presence of an ulcerated patch indicates either melanoma or basal cell carcinoma.
  • Melanoma on the foot. Asymmetric shape and color, and accompanying inflammation suggest melanoma.
  • Acral melanoma ― Nail in Asians. An irregular black patch that extends beyond the normal skin around the nail is an important finding that strongly suggests malignancy.
  • Although this case was diagnosed as melanoma, the visual finding is more similar to a nail hematoma. Nail hematomas (benign) typically disappear within one to two months as they are pushed out. Therefore, if the lesion persists for a long time, melanoma may be suspected and a biopsy should be performed.
  • Amelanotic nodular melanoma ― Unusual manifestation of melanoma.
References Malignant Melanoma 29262210 
A melanoma is a tumor produced by the malignant transformation of melanocytes. Melanocytes are derived from the neural crest; consequently, melanomas, although they usually occur on the skin, can arise in other locations where neural crest cells migrate, such as the gastrointestinal tract and brain. The five-year relative survival rate for patients with stage 0 melanoma is 97%, compared with about 10% for those with stage IV disease.
 European consensus-based interdisciplinary guideline for melanoma. Part 1: Diagnostics: Update 2022 35570085
Cutaneous melanoma (CM) is a highly dangerous type of skin tumor, responsible for 90% of skin cancer deaths. To address this, experts from the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO), and the European Organization for Research and Treatment of Cancer (EORTC) had collaborated.
 Immunotherapy in the Treatment of Metastatic Melanoma: Current Knowledge and Future Directions 32671117 
Melanoma is one of the most immunologic malignancies based on its higher prevalence in immune-compromised patients, the evidence of brisk lymphocytic infiltrates in both primary tumors and metastases, the documented recognition of melanoma antigens by tumor-infiltrating T lymphocytes and, most important, evidence that melanoma responds to immunotherapy. The use of immunotherapy in the treatment of metastatic melanoma is a relatively late discovery for this malignancy. Recent studies have shown a significantly higher success rate with combination of immunotherapy and chemotherapy, radiotherapy, or targeted molecular therapy. Immunotherapy is associated to a panel of dysimmune toxicities called immune-related adverse events that can affect one or more organs and may limit its use. Future directions in the treatment of metastatic melanoma include immunotherapy with anti-PD1 antibodies or targeted therapy with BRAF and MEK inhibitors.