Necrotizing sialometaplasia--a malignancy simulating oral lesion.

A case of necrotizing sialometaplasia is reported in a 63-year-old white male. The lesion appeared as an ulcerated and painful lesion inside the left ramus mandibulae. An incisional biopsy was performed and reported as well-differentiated squamous cell carcinoma. A few days after the initial biopsy was taken the necrotizing tissue disappeared and the ulcer started to heal. A new, excisional biopsy was performed. The initial diagnosis was revised and the lesion reported as necrotizing sialometaplasia. Two weeks after the excisional biopsy complete healing was obtained. The clinical and histological findings are discussed in relation to the different stages through which a necrotizing sialometaplasia might develop. From a differential diagnostic point of view it is important for both the clinician and pathologist to be aware of the lesion's behaviour during the different stages of development.