Final answer:
Congenital melanocytic naevi are moles present at birth that can develop into melanoma, demonstrated by asymmetry, irregular borders, variation in color, a diameter over 6 mm, and evolution over time. Additional signs of serious form include an elevated, firm, and growing naevus. Prompt medical consultation is crucial if these features are present.
Step-by-step explanation:
Features of a Congenital Melanocytic Naevus
A congenital melanocytic naevus is an accumulation of melanocytes, the pigment-producing cells, which is usually present at birth. These naevi, or moles, can develop into melanoma, a serious form of skin cancer. The features of congenital melanocytic naevus are:
- Asymmetry - the two halves of the naevus do not match, indicating non-uniform growth.
- Borders - the naevus has irregular and often poorly defined edges.
- Color - varying shades of brown or black are present, which can be unevenly distributed.
- Diameter - it may be larger than 6 mm, which is usually larger than many benign moles.
- Evolving - changes in the naevus over time could suggest malignancy, such as growth in size or alteration in shape.
Additional characteristics particular to nodular melanoma, a more severe type, include being elevated, firm, and continuously growing. Patients are often taught the ABCDE mnemonic to help recognize the early stages of melanoma which may stem from these naevi. If any of these features are observed, it's crucial to consult with a healthcare provider promptly.
Melanomas can appear as large brown or black patches with uneven borders and a raised surface suggesting progression from a benign mole to a malignant one. Early detection and treatment, such as surgical excision and immunotherapy, are critical to managing the disease.