Which best describes a flat lesion larger than 1cm?

A flat lesion larger than 1 cm is best described as a patch. Patches are defined as areas of skin that are distinctively different in color or texture from the surrounding skin and are greater than 1 cm in diameter. They can be indicative of various conditions, including pigmentary changes or inflammatory processes.

While papules are also flat lesions, they are specifically raised, typically measuring less than 1 cm. Vesicles, on the other hand, are small fluid-filled lesions, and plaques are raised lesions that could be larger than 1 cm but are not classified as flat; rather, plaques have a plateau-like structure. Therefore, the term "patch" accurately captures the characteristics of a flat lesion that exceeds 1 cm in size.