Necrotising sialometaplasia

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. 

Aetiology

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
  • smoking
  • cocaine use
  • upper respiratory infections
  • radiation
  • adjacent tumour growths
  • bulimia

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.

CT

Soft tissue density swelling of the palate which may show ulceration

MRI

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
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Article information

rID: 50872
System: Head & Neck
Section: Pathology
Synonyms or Alternate Spellings:
  • Necrotizing sialometaplasia

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