Abstract: Twenty-three cases of acinic cell adenocarcinoma(ACC)of salivary gland were studied with histochemistry and immunohisto chemistry staining compared with H-E-stained slides. It was shown that though the PASstain played an important role in diagnosis of ACC,this histochemical method has its limit. Because there were different reactions of PASin different types of ACC.However,another histochemical methods can be used easily for the differentia ldiagnosis of the ACC with the clear cells or the ACC with oxyphilic granules. Immunohistochemical staining for Keratin,S-100 protein and Carcinoembryonic antigen is of key importance in the differential diagnosis of ACC with low differentiation.The histogenesis of ACC is also discussed.

Key words: Acinic cell adenocarcinoma, Histochemistry, Keratin, S-100 protein, Carcinoembryonic antigen