Clinical classification of malignant melanoma of skin cancer

Malignant melanoma is a highly malignant skin cancer. It can be divided into the following four types according to the appearance of skin lesions, predilection sites, and degree of malignancy:

1. Acral lentiginous melanoma

This is a common type in my country, accounting for 50% of melanoma in Asians. It usually develops from acral lentigo and is more common on the palms, soles, and nails. The lesions are unevenly pigmented and have irregular borders. If located in the nail matrix, the nail plate and nail bed may show longitudinal band-like pigment stripes. This type progresses quickly, often increasing in size in a short period of time, ulcerating or metastasizing, and the survival rate is only 11% to 15%.

2. Lentigo maligna melanoma

It is common in the exposed parts of the elderly and often develops from malignant lentigo. The skin lesions are light brown or brown uneven pigmented patches with dark brown or black spots and irregular edges. This type grows slowly and metastasizes relatively late.

3. Typical nodular melanoma

It is common on the head, neck, trunk, soles, vulva, lower limbs, etc. The skin lesions initially appear as blue-black or dark brown raised nodules, which rapidly increase horizontally or vertically into papilloma-like shapes and may form ulcers.

4. Superficial spreading melanoma

It develops from superficial melanoma and is prone to occur on the trunk and limbs. The lesions are smaller than lentigo maligna, rarely exceeding 2.5 cm in diameter, and appear as irregular patches, some of which are arcuate, brown, or black. The presence of papules, nodules, induration, and ulcers on the lesions indicates a poor prognosis.