Histopathologic and immunohistochemical study in one case of cystadenoma of parotid gland becoming malignant.

Summary. Cystadenoma and cystadenocarcinoma of the salivary glands are rare tumors, approximately half of cases being diagnosed at the level of parotid. The studied tumor associated both benign and malign zones, with deep infiltrating character in the adjacent structures. In both areas the growing pattern was predominantly cystic and papillary, and the proliferated neoplastic cells were majority cubical or columnar, with low grade of nuclear pleomorphism in the becoming malign areas, discordant with the infiltrative character of the neoplasm. Immunohistochemically, we investigated the tumor with AE1-AE3, CEA, SMA, S-100 and PCNA.