INTRODUCTION AND OBJECTIVE: The pleomorphic adenoma is the most common salivary gland tumor. The parotid gland is the most frequent anatomic site. Its clinical and microscopic features are widely known. However, its pathogenesis is still uncertain as well as the expression of oncogenes and other factors that influence malignant transformation. The objective of this study was to analyze the histopathological features of malignant transformation in pleomorphic adenoma (PA) of major salivary gland and correlate them with p53 protein expression in these tumors. MATERIAL AND METHOD: We evaluated 106 cases of PA by researching clinical records retrospectively, reviewing histological preparations in HE and applying immunohistochemical technique through streptavidin biotin method using primary anti-p53 antibody. RESULTS: Histopathological changes related to malignant transformation were unusual: extensive hyalinization (5; 4.7%) and necrosis (1; 0.9%). There was positivity for p53 protein in 25 out of 106 cases (23.58%). The histological cell arrangement of p53 - positive tumors was mainly the ductal type (92%; 23) and cordonal (88%, 22). There was no statistically significant association between positivity for p53 and histopathological variables in comparison with negative cases: quantity and type of extracellular matrix, tissue changes suggestive of malignant transformation and metaplasia. CONCLUSIONS: A few cases that showed p53 expression had some kind of morphological change suggestive of malignancy and the correlation between p53 immunoexpression and the presence of changes suggestive of malignant transformation was not statistically significant, which suggests that the protein expression in these tumors do not depend on these characteristics.
Pleomorphic adenoma; Major salivary glands; Malignant transformation; p53; Salivary gland neoplasm
