A 63-year-old man presented to his family physician for a follow-up visit. He was wearing a mask, and at the end of the appointment, he asked the physician to assess a lesion on his lip. The lesion had progressively worsened over six months, during mandated use of masks. The lesion was painful with intermittent bleeding. The patient did not use chewing tobacco but was a daily smoker. He had a history of fever blisters and significant sun exposure as a child. He did not have weight loss, other skin lesions, or family history of skin conditions.

Physical examination revealed an ulcerated, crusted, erythematous plaque with well-demarcated borders on his lower lip (Figure 1). Biopsy was performed to further characterize the lesion.

Question

Based on the patient’s history and physical examination findings, which one of the following is the most likely diagnosis?

• A. Actinic cheilitis with squamous cell carcinoma in situ.

• B. Basal cell carcinoma.

• C. Keratoacanthoma.

• D. Lichen planus.

• E. Squamous cell carcinoma.