A 70-year-old patient with a non-healing ulcer on the lower lip, sun-damaged skin, and regional lymphadenopathy is found to have well-differentiated squamous cell carcinoma. The precursor lesion most directly leading to lip SCC is:

• A Actinic chelitis (actinic keratosis of the vermilion border) ✓
• B Sebaceous hyperplasia
• C Discoid lupus erythematosus scar
• D Leukoplakia — white patch unrelated to actinic damage

Explanation

Actinic cheilitis is the direct precursor to SCC of the lower lip, analogous to actinic keratosis on the skin, caused by cumulative UV-B irradiation. The lower lip is more exposed to UV than the upper lip, explaining its predilection. It presents as irregular white/grey patches or erosions on the vermilion border with loss of the lip-skin junction. Transformation rate to SCC is higher than actinic keratosis on the skin. Treatment includes 5-FU, imiquimod, vermilionectomy, or photodynamic therapy.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.