Cytodifferentiation to Serous and Myoepithelial Cells in Salivary Gland and Salivary Gland Type Tumors

Three-hundred-and-three cases of salivary gland and salivarygland type tumors in the head and neck and lower respiratorytract, treated in our institution, were reviewed histologically.Some of these cases were analyzed; 51 arbitrarily selected casesby conventional stainings, 15 cases by immunostainings for amylaseand actomyosin, and 22 cases by electron microscopy for cellulardifferentiation to serous and myoepithelial cells For morphologicaland biochemical comparison, six cases of ectopic amylase-producingtumor were also studied Serous acmar cells contained amylaseand basaly located cells of acini and ducts contained actomyosinin non-neoplastic salivary glands Although zymogen type granuleswere barely observed except in a case of acinic cell carcinomaof the palate and in a case of adenocarcinoma of the lung bylight and electron microscopy, some tumor cells contained amylasewhich seemed to be specific of salivary gland tumor in threecases and of ectopic amylase-producing tumor in three cases,confirmed by immunofluorescent microscopy, enzyme assay andelectrophoresis of the tumor tissues In cases of mixed tumor, adenoid cystic carcinoma, and mucoepidermoidcarcinoma, cells reactive to anti-actomyosin were often encounteredin the outer layer of duct-like structures By electron microscopy, location of myoepithelium-like cellswas in accord-ance with that of actomyosin-positive cells insome instances Coexistence of tonofibrils and myofilaments inone and the same cell was occasionally seen ^* Present address: Department of Pathology, Tokai UniversitySchool of Medicine, Kana gawa, Japan.