Clinical Features:

• Common preneoplastic lesion most often seen on sun-exposed skin of the elderly
• Approximately 1 in 1000 untreated actinic keratoses eventually evolve into squamous cell carcinoma, and patients with actinic keratoses have a markedly increased risk of developing squamous cell carcinoma.
• Risk factors include prolonged skin exposure and fair skin.
• Most commonly presents as a small, well-demarcated hyperkeratotic growth, with several described variants which are associated with their own clinical appearances.

Histologic Features:

• Hyperparakeratosis, often with loss of the granular layer
• Proliferation of the basal layer with slight budding into the dermis
• Basal layer atypia: increased mitoses, enlarged nuclei with prominent nucleoli, increase or decrease in basophilia compared to surrounding keratinocytes
• There is often mild spongiosis above the atypical basal layer.
• Liquefactive degeneration of the basal layer may occur.
• Focal to widespread acantholysis may occur.
• Mild upper dermal perivascular lymphocytic infiltrate

Cases associated with this book:

Actinic keratosis
Author: Artur Zembowicz M.D. Ph.D.

Conference: DermatopathologyConsultations.com Teaching Collection