Imaging Studies
A definitive tissue diagnosis of necrotizing sialometaplasia should exclude the need for radiographic imaging. If erosion of the palatal bone occurs with or without perforation, radiologic examination may be performed. [24]
Procedures
Incisional biopsy is necessary to establish the diagnosis of necrotizing sialometaplasia (NS). An inadequate biopsy specimen may lead to the misdiagnosis of squamous cell carcinoma or mucoepidermoid carcinoma. Findings in a superficial or limited biopsy specimen may be misinterpreted as a nonspecific ulcer or pseudoepitheliomatous hyperplasia of the surface mucosa.
Histologic Findings
The microscopic features of necrotizing sialometaplasia include coagulative necrosis of glandular acini and squamous metaplasia of its ducts. Mucin pooling is present, and an associated inflammatory infiltrate consists of macrophages; neutrophils; and, less commonly, lymphocytes, plasma cells, and eosinophils.
Pseudoepitheliomatous hyperplasia of the overlying mucosa can also be present, but the cytologic features of the squamous component are usually bland. Occasionally, isolated mucous cells may be entrapped within the squamous islands; these cells should not be confused with those of mucoepidermoid carcinoma.
The microscopic differential diagnosis for necrotizing sialometaplasia includes mucoepidermoid carcinoma and squamous cell carcinoma. Some believe that subacute necrotizing sialadenitis is yet another entity that occurs within the spectrum of necrotizing sialometaplasia; it should be distinguished from necrotizing sialometaplasia.
-
Initial presentation.
-
Three weeks later after biopsy.
-
At 6 weeks.
-
Nine weeks. Salivary gland infarction.
