A patient presents with recurrent vesicular lesions confined to the hard palate that have been appearing in the same location for years. The MOST likely diagnosis is:

Correct answer: C. Recurrent intraoral herpes (RIH)

• A. Aphthous ulcers occur on MOVABLE (non-keratinized) mucosa (buccal mucosa, soft palate, floor of mouth) — NOT the hard palate. They also do not start as vesicles.
• B. Primary VZV (chickenpox) causes widespread lesions; shingles is unilateral and does not cross the midline. Neither recurs in the same oral location repeatedly.
• C. Correct. Recurrent intraoral herpes (caused by HSV-1 reactivation) characteristically affects ATTACHED (keratinized) mucosa — particularly the hard palate and attached gingiva — in the same location each time. It presents as clusters of small vesicles/ulcers. Recurrence in identical location is the key feature distinguishing it from aphthous ulcers.
• D. Pemphigus vulgaris produces widespread erosions and blisters across multiple sites — not recurring in one fixed location.