Radiographic Findings of Necrotizing Sialometaplasia

Necrotizing sialometaplasia (NS) is a benign self-limiting inflammatory disease of salivary glands, mainly involving the minor salivary glands in the palate. This lesion can mimic a malignant neoplasm, manifesting as a submucosal swelling or as an ulcer of the palate. Radiographic features of NS were rarely reported in the literature.

We present a case of an otherwise healthy 20 year old male, who arrived to the emergency room in Rambam Health Care Campus in Haifa, Israel, due to acute excruciating pain in his palate and oropharynx combined with a tingling numbness is the palate and an extreme throbbing headache, for the last two days which later diagnosed with bilateral NS in the palate. To the best of our knowledge, this is the first report describing imaging features of NS in the swelling phase.

We present computed tomography findings in a patient with bilateral palatal NS who smoked and used anabolic steroids. Review of the literature revealed only another 2 cases of palatal NS which underwent imaging work-up, performed in the ulceration phase in both cases. The CT scan demonstrated diffuse edema without enhancement of the mucosa overlying the hard palate. No other pathological findings were detected.

Although pathological characteristics of NS have been studied and reported extensively, imaging features of NS has rarely been reported. Only two cases were reported in the posterior palate, and both of them were performed after the ulceration phase. To the best of our knowledge, imaging features of palatal NS in the swelling phase has not been reported. 24 cases of imaging features of parotid NS cases were reported and discussed elsewhere⁸.

An incisional biopsy was performed to confirm the diagnosis. Pathological findings were consistent with NS. The patient was instructed to use analgesics, chlorhexidine mouth wash and refrain from smoking. Full healing was reached after 10 weeks.

To conclude, we described CT findings of NS in the pre-ulceration phase. Radiographic findings seem to vary depending on the stage, as seen also in the histologic stages. Recognition of NS is essential because this lesion may mimic malignancy both clinically and histologically. Radiographic findings including fluid-like appearance and absence of contrast enhancement may aid the clinician in definitive diagnosis.