[Salivary gland tumors: pathology and prognosis]

Due to their infrequency, diagnosis of salivary gland tumors remains a challenge for the practicing pathologist with respect to subtyping, grading and estimating patient prognosis. In a 3 center collaborative study of 288 cases with clinical follow-up information, it could be demonstrated that apart from clinical parameters like high patient's age, male sex and high tumor stage, the application of a 3-tiered grading system incorporating the histological tumor type is of high prognostic relevance. In immunohistochemical and molecular analyses overexpression of epidermal growth factor receptor (EGFR), high expression of human epidermal growth factor receptor 2 (HER2), amplification and gains of EGFR and HER2, absent expression of C-KIT, loss of maspin and of O(6)-methylguanine DNA-methyltransferase (MGMT) as well as MGMT promoter methylation turned out to be negative prognostic factors. In mucoepidermoid carcinomas the presence of a translocation t(11;19) was less relevant than recognizing different subtypes (classical type, eosinophilic, clear-cell and squamoid variants). Acinic cell carcinoma with mixed acinar-ductular differentiation as judged by expression of CK7 was characterized by a higher frequency of early relapse. The presented results underline the pathologist's role in the diagnosis and management of patients with salivary gland carcinomas.