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sclerosing sialadenitis

Monday 5 November 2007

Definition: Chronic sclerosing sialadenitis (CSS) is a cryptogenic tumor-like condition of the salivary gland(s).

Küttner, in 1896, described a series of patients with a unilateral, hard, tumor-like mass of the submandibular gland, which histologically showed features of chronic sclerosing sialadenitis. Because of its tumor-like presentation, this lesion has come to be known as Küttner’s tumor.

Patients are more often male than female, with a median age of 44 years. They present with a rock-hard, unilateral mass, which is often painless but may be associated with pain on food ingestion. It is not associated with Sjögren’s syndrome or other autoimmune disease, and very rare progression to lymphoma has been reported.

The histologic features of chronic sclerosing sialadenitis in most cases are different from those of LESA. The ducts are typically dilated and filled with inspissated secretions; sialoliths are found in 50-80% of the cases.

Prominent periductal fibrosis, associated with a lymphoplasmacytic infiltrate, may contain reactive follicles and germinal centers. Lobular fibrosis and acinar atrophy are seen in advanced cases.

Although the lymphoid infiltrate may be prominent, the presence of marked fibrosis and relative lack of epithelial proliferation, in most cases, distinguish Küttner’s tumor from typical LESA. There may be morphologic overlap in some cases, and lymphoepithelial lesions have been described in Küttner’s tumor. (11717546)

Pathogenesis

The pathogenesis of chronic sclerosing sialadenitis is postulated to be duct obstruction by abnormal secretions, termed obstructive electrolyte sialadenitis.

However, the presence of reactive follicles in most cases indicates an immunologic component to the process. Thus, it is possible that the setting of chronic immune stimulation resulting from mechanical duct obstruction and release of antigens from parenchymal cells provided a substrate for the very rare development of a MALT lymphoma. (11717546)

The absence of lymphoepithelial lesions may reflect biologic differences in the epithelium of the submandibular gland duct epithelium compared with the parotid, which is the site of most salivary MALT lymphomas.

Even in Sjögren’s syndrome, the lesions of the submandibular and intraoral salivary glands often show less epitheliotropism than those in the parotid. Furthermore, MALT lymphomas of other epithelial sites (lacrimal gland, skin, breast) often lack prominent lymphoepithelial lesions. (11717546)

It is also possible that the nature of the immune stimulus in Küttner’s tumor is different from that usually present in Sjögren’s syndrome/LESA, resulting in neoplastic cells with different epitheliotropism or that the damage to the ducts by the obstructive sialadenitis may alter the relationship of the neoplastic marginal zone cells to the epithelium. (11717546)

Synopsis

- periductal fibrosis and dilated ducts
- prominent lymphoid infiltrate surrounding the areas of fibrosis
- atrophic salivary parenchyma with preservation of lobular architecture
- no intraepithelial lymphoid infiltration
- no lymphoepithelial lesions (epimyoepithelial islands)

See also

- salivary lesions