A 65-yrs-old man who is a long-time farmer presents with a small, scaly erythematous lesion on the helix of his left ear. A biopsy from this lesion reveals marked degeneration of the dermal collagen along with atypia of the squamous epidermal cells. The atypia, however, does not involve the full thickness of the epidermis, and no invasion into the underlying tissue is seen. Which of the following is the most likely diagnosis? (AIPG 2012)
a. Actinic (solar) keratoses, found on sun-damaged skin, microscopically show hyperkeratosis, parakeratosis, atypia of the epidermal keratinocytes, and degeneration of the elastic fibers in the dermis (referred to as solar elastosis).
b. Clinically, actinic keratoses appear as irregular erythematous brown papules.
c. When the atypia of the intraepidermal keratinocytes is extreme (full thickness), the lesion is referred to as Bowen’s disease (carcinoma in situ).