Tumeurs des glandes salivaires. État des lieux en 2009

Abstract

Histologic grade is a significant predictor of outcome in salivary gland carcinomas. We underlined some newly recognized findings in grading: (i) evidence of high grade anaplastic transformation, occurring either at initial presentation or at relapse, is correlated with the clinical outcome; (ii) extracapsular invasion of carcinoma ex pleomorphic adenoma should be measured because it is now a known prognostic marker; (iii) the MIB-1 proliferative index is the most useful immunohistochemical marker for prognosis of all salivary gland carcinomas. In recent years, specific chromosomal translocations have been reported in some salivary glands tumors. The PLAG1 and HMGA2 gene translocations have so far been identified only in pleomorphic adenomas, and their detection may potentially aid in diagnosis. The mucoepeidermoid carcinoma translocated 1--mastermind like gene family (MECT1-MAML2) translocation, characterizing mucoepidermoid carcinoma, is also a prognostic marker. Newly recognized entities are summarized with special interest on differential diagnosis pitfalls: oncocytic mucoepidermoid carcinoma, sclerosing mucoepidermoid carcinoma with eosinophilia, sclerosing polycystic adenosis, lymphadenoma, lipoadenoma, newly recognized morphological variants of epithelial-myoepithelial carcinoma, cribriform adenocarcinoma of the tongue, signet ring adenocarcinoma of minor salivary gland. Specific chromosomal translocations and latest knowledge of the molecular mechanisms responsible for salivary glands oncogenesis (Epidermal Growth Factor Receptor [EGFR], phosphorylated AKT, topoisomerase II alpha, p27, Stat 3, maspin) should pave the way toward future targeted therapies.