Snapshot A 74-year-old man presents to the dermatologist’s office for his annual total body skin exam. His past medical history is significant for multiple actinic keratoses, previously treated with cryotherapy. At this visit, he points to a larger lesion on his ear, complaining that it grew back after last year’s cryotherapy. A shave biopsy was done and pathology reveals malignant cells invading the dermis. He is scheduled for an excision. Introduction Invasive primary skin malignancy arising from keratinocytes of skin or mucosa Keratoacanthoma is a variant of low-grade squamous cell carcinoma login to view 1 more bullet Bowen disease is a kind of cutaneous squamous cell carcinoma in situ that usually appears login to view 4 more bullets Epidemiology Common in fair-skinned individuals Common in elderly patients 2nd most common form of skin cancer (first is basal cell carcinoma ) Major risk factor = significant sun exposure (damage to keratinocytes) login to view 2 more bullets Other risk factors login to view 5 more bullets ETIOLOGY Pathogenesis login to view 3 more bullets Presentation Symptoms login to view 1 more bullet Physical exam login to view 11 more bullets STUDIES Diagnosis by skin biopsy login to view 3 more bullets Differential Actinic keratosis Actinic cheilitis Treatment Prevention login to view 2 more bullets Wide local surgical excision login to view 1 more bullet Radiation if surgery is not an option Complications Potential recurrence if immunosuppressed Prognosis If treated, very excellent prognosis Lesions on lip, ear, or scalp may be more aggressive