Final answer:
Melanoma often develops from a mole and is characterized by atypical patches with uneven borders. It is crucial to detect it early for effective treatment.
Step-by-step explanation:
Melanoma frequently arises from the transformation of a mole into a cancerous lesion. It is characterized by the uncontrolled growth of melanocytes, which are the pigment-producing cells located in the epidermis. Often, melanomas present as large, asymmetrical brown or black patches with uneven borders and a raised surface. It is the most serious, although rarer, form of skin cancer, and is known for being highly metastatic. Early detection is crucial for treatment, which may involve surgical excision and immunotherapy.