Abstract

Salivary gland tumors are unique among head and neck tumors in the wide array of pathology that they manifest. Billroth (1859) first described four different types of tissue in salivary gland tumors. Since then two theories, mesenchymal and epithelial, have prevailed as to the histogenesis of salivary gland tumors, particularly the so called mixed tumor. Nowadays, the epithelial theory, though not firmly established, enjoys wide support. Recent advances in histochemical techniques have helped to characterize and differentiate sugar containing compounds. Although there are a number of studies concerning the characteristics and distribution of mucoid material found in the salivary gland tumors, a more systematic histochemical study would to of help in the further investigation of the histogenesis of various salivary gland tumors. We have attempted to classify an assortment of salivary tumors on histological basis and performed histochemical studies using various special stains. Material and Methods The material consists of 110 salivary gland tumors examined at the Department of Pathology, Yonsei University College of Medicine between 1969 to 1979. All cases were subjected to histochemical analysis and further morphological study. The paraffin blocks were sectioned serially at 5-7μ and sections stained with hematoxylin and eosin, periodic acid-Schiff reagent (PAS), PAS after diastase digestion, Best's carmine, alcian blue, and toluidine blue. For control of toluidine blue staining, sections of umbilical cord were used. Results and Summary Following results are obtained from histopathologic studies and histochemical analysis on the 110 cases of salivary gland tumors. 1) Out of 110 cases 69 cases(62.7%) occurred at the major salvary gland and 76 cases(69.1%) were benign. 2) Of these major salivary gland tumors 15 cases(21.7%) were malignant while 16 cases (44.4%) of minor salivary gland tumors(total of 36 cases) were malignant. 3) In all salivary glands, there was a striking predominance of pleomorphic adenoma comprising 72 cases(65.5%) of salivary gland tumors. The second largest group observed was adenoid cystic carcinoma followed by mucoepidermoid tumor. 4) Mucoid material found in the ductal lumen of pleonlorphic adenoma, mucoepidermoid tumor and adenoid cystic carcinoma was diastase-reaistant PAS positive. Material in the pseudocystic spaces of adenoid cystic carcinoma was strongly alcian blue positive, toluidine blue positive, and metachromatic. 5) Mucoid material in the stroma of salivary gland tumor was alcian blue positive, toluidine blue-positive and metachromatic. Results of the present study indicated that the epithelial cells of pleomorphic adenoma, mucoepidermoid tumor and Warthin's tumor in addition to the duct lining cells of adenoid cystic carcinoma were derived from duct epithelia which secrete neutral mucopolysaccharide. The cells forming both pseduocyst in the adenoid cystic carcinoma and chondromyxoid area in the pleomorphlc adenoma were thought to originate from mesenchymal cells which secrete acid mucopolysaccaride.