[Küttner's tumour (chronic sclerosing sialadenitis). Clinical, pathological, and immunohistochemical study in 8 cases of a little-known entity].

OBJECTIVE To present the clinical-pathological characteristics of Küttner's tumour (KT) or chronic sclerosing sialadenitis. MATERIAL AND METHOD We studied 8 cases of KT that were graduated histologically according to the Seifert grading system. An immunohistochemistry panel including CD20, CD3, and keratin AE1-3 was performed. RESULTS All cases involved the sub-maxillary gland. Microscopically the cases were in stages 2, 3, and 4. There was a chronic inflammatory infiltrate, marked fibrosis, variable degrees of parenchymal atrophy, PAS+ intraluminal material, and microliths. The infiltrate was polymorphic and polyclonal, without lymphoepithelial lesions. CONCLUSIONS Although it has a typical clinical and pathological presentation and was described more than a century ago, KT remains under-diagnosed and often reported as non-specific inflammatory infiltrate or as "low grade lymphoma". In this latter diagnosis lies the greatest importance for recognizing KT, as confusion with lymphoma would result in a different therapeutic approach.