What type of lesions cast a shadow outside their edges, such as warts or blisters?

Elevated lesions are those that rise above the surface of the surrounding skin. This elevation causes them to cast a shadow around their edges, which is an important visual cue in dermatology. Warts and blisters are classic examples of elevated lesions. Warts are caused by viral infections and manifest as raised, rough patches of skin, while blisters are formed from fluid accumulation beneath the skin surface, creating a bulging structure. The shadow cast by these lesions enhances their visibility and characteristics, allowing for easier identification by healthcare professionals or during exams.

In contrast, flat lesions do not protrude from the skin surface, so they would not cast a shadow or have the same visibility. Depressed lesions, on the other hand, are below the skin's normal surface and would not be able to create a shadow effect. Linear lesions refer to those that appear in a line or strip form and do not fit the criteria of casting a shadow outside their edges either. Thus, elevated lesions are distinctly recognized for their ability to cast shadows, making them the correct choice in this inquiry.