Final answer:
A junctional melanocytic naevi is a benign mole at the dermoepidermal junction, unlike melanomas which display asymmetry, irregular borders, varied colors, and changes in size and shape, signaling potential malignancy.
Step-by-step explanation:
A junctional melanocytic naevi refers to a type of mole located at the dermoepidermal junction, which is the area between the dermis and epidermis layers of the skin. These are benign accumulations of melanocytes, the cells responsible for skin pigment. Unlike melanomas, which can develop from moles and are characterized by uncontrolled growth of melanocytes, junctional naevi are typically flat and have a uniform color. Melanomas often present as large, asymmetrical patches, with varied shades of brown or black, uneven borders, and can be raised with a diameter larger than 6 mm and change shape over time, making them the most fatal form of skin cancer.
To differentiate between a benign mole and a potential melanoma, doctors recommend using the ABCDE mnemonic; Asymmetry (the two sides are not symmetrical), Borders (irregular shape), Color (varied shades), Diameter (larger than 6 mm), and Evolving (shape has changed). Following this guide can help in the early diagnosis of melanoma.