Final answer:
An asymmetrical lesion is a dermatological finding with mirror-image halves on either side of a center line, important for the diagnosis of skin conditions.
Step-by-step explanation:
An asymmetrical lesion is a dermatological finding where the lesion, or area of damage to the skin, has a uniform shape and size on both sides of a center line. That is, if you were to draw a line through the middle of the lesion, both halves would mirror each other. This symmetry can be an important clue in diagnosing particular skin conditions or diseases. For instance, certain autoimmune disorders may present with symmetrical lesions, whereas asymmetrical lesions might suggest different types of skin conditions such as melanoma, which are often characterized by having an irregular border and varying coloration. It is important to consider that a symmetrical lesion shares these qualities irrespective of the underlying cause, whether it be inflammation, exposure to toxins, or genetic disorders like Xeroderma pigmentosa, where UV damage is not repaired, leading to characteristic skin lesions.