9th July 2023

Melanoma Skin Cancer (MSC)

Risk factors

Melanoma is the most aggressive form of skin cancer arising from uncontrolled proliferation of melanocytes, which reside in the epidermis. Environmental and genetic risk factors (such as xeroderma pigmentosum) are important. Like Non-Melanoma Skin Cancer (NMSC), these include UV damage, fair features, and immunosuppression. Personal history of any skin cancer, family history, >50 naevi or >5 atypical naevi (≥6mm) should also be considered.

Types

Clinical presentation depends on the type of melanoma (see table 3). Rarer forms include amelanotic, mucosal and ocular.

Table 3: Table outlining the more typical forms of melanoma with associated details

Extensive acral lentiginous melanoma of the left sole of the foot.

Image Source: Wikimedia Commons (2020). Photography of a large acral lentiginous melanoma, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Photography_of_a_large_acral_lentiginous_melanoma.jpg (Accessed on: 2 November 2021).

Investigation/Treatment

The ABCDE approach can be useful for detection. Other signs include itching, bleeding, and tenderness. A full-thickness excisional biopsy is diagnostic and prognostic. Breslow’s thickness (invasion depth) is an important prognostic marker and informs the margins of further surgery (Wide local Excision [WLE]). A WLE assists with staging and can be therapeutic. Sentinel lymph node biopsy (SLNB) can detect melanoma spread to nearby lymph nodes, which may indicate further dissection and imaging with CT, MRI, or PET scans. Adjuvant treatments include immunotherapy and targeted therapies.