A nodular BCC has a pearly, translucent quality and lacks the central keratin-filled crater that is the hallmark of a keratoacanthoma.
These are intensely itchy, excoriated nodules, whereas a KA is typically a non-pruritic, rapidly growing tumor.
A PG is a bright red, friable, vascular tumor that bleeds easily, unlike the firm, skin-colored, keratin-plugged nodule of a KA.
This is the most important differential; a KA is defined by its very rapid growth and tendency for spontaneous involution, whereas a conventional SCC has slow, progressive growth and does not involute.
A common wart has a papillomatous, verrucous surface, unlike the smooth-shouldered, crater-like morphology of a KA.
