ABSTRACT
Subungual keratoacanthoma is a benign, rare, and rapidly (within weeks) growing painful nodule with a central crater filled with keratin. Underlying bone erosion is common. It is usually located below the free edge of the nail plate or in the most distal portion of the nail bed. The nail plate is usually deformed and irregularly enlarged with superficial fissuring and mild subungual hyperkeratosis, clearly detectable with dermatoscopy ( Figure 24.1 ).
