What is the most serious form of skin cancer characterized by dark patches on the skin?

Malignant melanoma is recognized as the most serious form of skin cancer due to its ability to spread rapidly to other parts of the body if not detected early. It typically manifests as dark patches on the skin, which can arise from existing moles or appear as new, irregularly shaped growths. The distinctive pigmentation is caused by malignant melanocytes, the cells that produce melanin, leading to the characteristic dark spots.

The aggressive nature of malignant melanoma underscores the importance of catch and treatment, as late-stage diagnosis significantly impacts prognosis. In contrast, basal cell carcinoma and squamous cell carcinoma, while they can be serious, usually do not have the same extensive potential for metastasis or mortality as malignant melanoma. Kaposi sarcoma, although also a serious condition, is related to immunosuppression and presents differently, often as purplish or brownish lesions rather than exclusively dark patches. Therefore, the recognition of dark patches indicates a need for immediate medical evaluation to determine if it is malignant melanoma.