Classification of the Pathohistology of Diseases of the Salivary Glands — Review of 2,600 Cases in the Salivary Gland Register

Abstract

Three major disease groups emerge from a classification of the pathohistology of 2,600 salivary gland preparations in the salivary gland register (from 1965 to 1974): salivary gland tumors (41%), salivary gland inflammations (26%), and sialadenosis (6%). Mucoceles (2%) and salivary gland cysts (1.5%) are seen less often. It is diagnostically important that lymph node changes in the area of the salivary glands (lymphadenitis, lymphomas, etc.) are worked up under suspicion of a primary salivary gland disease. Sialadenosis involves a primary, vegetative neuropathy, which is accompanied by enlargement of acinar cells. Under the heading of chronic sialdenitis, we fine 50% socalled Küttner tumors of the submandibular gland, 21% chronic relapsing parotitis, 14% chronic inflammations of the minor salivary glands and the sublingual gland, and 12% immune sialadenitis (myoepithelial sialadenitis in Sjögren's syndrome and epitheloid cell sialadenitis in Heerfordts syndrome). A more than average number of immune sialadenitis cases develop into malignant lymphomas (4 cases in the salivary gland register). The 1,067 tumor cases containing of 929 epithelial tumors (87%), 89 mesenchymal tumors (hemangiomas, lymphangiomas, lipomas, neurofibromas, sarcomas) and 49 metastases or periglandular tumors. Epithelial tumors were grouped on the basis of the World Health Organization (WHO) classification. Benign tumors (71.5%) consisted of pleomorphic adenomas (51.5%) and monomorphic adenomas (50%). After the pleomorphic adenomas, cystadenolymphomas (over 10%) represented the most frequent benign salivary gland tumor. On the basis of epithelial and stromal differentiation, pleomorphic adenomas were subdividied into four subtypes (stroma-rich and stroma-poor adenomas). The malignant tumors consisted of acinar cell tumors (2.5%), mucoepidermoid tumors (6%), and carcinomas at various levels of differentiation (adenoid-cystic carcinomas, 6.5%; adenocarcinomas, 2%; squamous cell carcinomas, 2%; carcinomas in pleomorphic adenomas, 4%; miscellaneous carcinomas - salivary duct carcinomas, clear-cell carcinomas, undifferentiated carcinomas, 5.5%). Differences in age and sex distribution, localization, malignity metastases, recidivism, et