A patient presents with a 4 mm candida-like lesion on the gingival mucosa in the upper premolar region. Nystatin treatment has failed to resolve the lesion. What is the most appropriate next step?

Correct answer: D. Incisional biopsy

• A. Excisional biopsy (complete removal) is preferred for small lesions (<1 cm) that are clearly benign in appearance and can be entirely excised for diagnosis. For a persistent undiagnosed lesion, incisional biopsy first establishes the diagnosis.
• B. Exfoliative cytology (brush biopsy) is a screening tool but not definitive. A failed treatment course warrants definitive histopathologic diagnosis via incisional biopsy.
• C. Trying another antifungal (fluconazole) for a lesion that has already failed nystatin delays diagnosis when the lesion may not be candida. Biopsy should be done at this point.
• D. CORRECT. When a presumed candidal lesion does not resolve after adequate antifungal treatment, the diagnosis must be questioned. A lesion persisting despite treatment warrants biopsy to rule out leukoplakia, squamous cell carcinoma, or other pathology. Incisional biopsy is appropriate for lesions >1 cm or when malignancy cannot be excluded — the 4mm size and failed treatment justifies tissue sampling.