Nonmelanoma skin cancer of the head and neck: clinical evaluation and histopathology.

Clinical and histopathologic features of nonmelanoma skin cancer, physical examination, and diagnostic methods (biopsy, dermoscopy, confocal microscopy) are summarized. A diagnostic algorithm provides a useful summarization of differential diagnosis of basal cell carcinoma, actinic keratosis, Bowen's disease, and squamous cell carcinoma.