Necrotising sialometaplasia is a benign inflammatory condition of the salivary gland remnants or elements, which is usually self-limiting. It is most commonly found in the palate.
Most patients are more than 40 years of age, with a male:female ratio of 2:1. It is rarely seen in children. The palate is the most common site involved, usually located in the back of the hard palate.
Starts as non-ulcerated swelling with pain. In 2-3 weeks, the necrotic tissue leads to ulcer(s). The condition is usually self-limiting and shows complete remission subsequently without treatment within 6 to 10 weeks.
Uncertain, possibly secondary to ischaemia of the salivary tissue leading to infarction. Other postulated causes include:
- abnormal dentures causing chronic irritation to the palate
- following adenoidectomy in children
- prior surgery
- local trauma
- dental injections
- alcohol abuse
- cocaine use
- upper respiratory infections
- adjacent tumour growths
Acinar necrosis is found in early lesions. Subsequently, concomitant squamous metaplasia is seen. Despite necrosis, the lobular architecture of the glands is preserved. Metaplasia may mimic a malignant lesion, hence recognition of this condition is paramount.
Five histological stages have been described: infarction, sequestration, ulceration, reparation and healed.
Despite squamous metaplasia, malignant transformation is very rare.
Soft tissue density swelling of the palate which may show ulceration
They are seen as lobulated submucosal palatal lesions
- T1: hypointense
- T2: hyperintense
- T1 C+: thin peripheral enhancement
Possible differential considerations include
- mucoepidermoid carcinoma
- squamous cell carcinoma
- granulomatous diseases (syphilitic gumma)
- fungal infections
- 1. Suomalainen A, Törnwall J, Hagström J. CT findings of necrotizing sialometaplasia. Dento maxillo facial radiology. 41 (6): 529-32. doi:10.1259/dmfr/53649200 - Pubmed
- 2. Brannon RB, Fowler CB, Hartman KS. Necrotizing sialometaplasia. A clinicopathologic study of sixty-nine cases and review of the literature. Oral surgery, oral medicine, and oral pathology. 72 (3): 317-25. Pubmed
- 3. Farina D, Gavazzi E, Avigo C, Borghesi A, Maroldi R. Case report. MRI findings of necrotizing sialometaplasia. The British journal of radiology. 81 (966): e173-5. doi:10.1259/bjr/51447334 - Pubmed
- 4. von Stempel C, Morley S, Beale T, Otero S. Imaging of palatal lumps. Clinical radiology. 72 (2): 97-107. doi:10.1016/j.crad.2016.10.007 - Pubmed