A superficial BCC is distinguished by its pearly, thread-like border and fine surface telangiectasias, which are absent on the rough, scaly surface of an AK.
This is a single, exquisitely tender papule located specifically on the helix or antihelix of the ear, unlike the typically non-tender, scaly patches of AKs.
The key sign is its 'stuck-on,' waxy appearance that can often be peeled or scraped off, which is very different from the gritty, adherent scale of an actinic keratosis.
SCC is distinguished from its precursor, AK, by being thicker, more indurated, and often tender or ulcerated, indicating invasion into the dermis.
This presents as a shiny, pinkish patch with a fine, pearly border, lacking the characteristic rough, sandpaper-like feel of an actinic keratosis.
A flat wart can mimic an AK, but warts are distinguished by the presence of tiny black dots (thrombosed capillaries) upon paring the surface.
