A firm, indurated ulcerated lesion is present on the ventrolateral surface of the tongue in a 60-year-old smoker. What is the MOST likely diagnosis?

Correct answer: B. Squamous cell carcinoma

• A. Lichen planus presents bilaterally on the buccal mucosa with Wickham striae; the erosive form is painful but not indurated.
• B. CORRECT. The posterior LATERAL BORDER and VENTRAL surface of the tongue, along with the floor of the mouth, form the highest-risk region of the oral cavity for SQUAMOUS CELL CARCINOMA. Key clinical features: INDURATION (firmness on palpation), rolled or everted borders, ulceration that fails to heal in 2 weeks, fixation to underlying tissue, and painlessness early on. Any such lesion requires INCISIONAL BIOPSY.
• C. A traumatic ulcer has an identifiable cause and heals within 10–14 days after removing it — persistence beyond 2 weeks demands biopsy.
• D. Nicotinic stomatitis is confined to the HARD PALATE of pipe/cigar smokers — a white palate with red punctate minor salivary duct openings. It has essentially no malignant potential in that location (reverse smoking is the exception).

Note: The 2-week rule: any oral ulcer that has not healed in 2 weeks after removing obvious causes must be biopsied.