Morphological features of recurrent pleomorphic adenomas of the major salivary glands

Objective. To investigate morphological features of recurrent pleomorphic adenoma on the operative material of parotid salivary glands. Materials and methods. 40 cases of primary pleomorphic adenomas of the parotid salivary glands and 30 cases of recurrence of this tumor were analyzed. A comparative evaluation of various structural changes in the tumor tissue on the basis of complex morphological and immunohistochemical studies was performed. Frequency analysis between groups was performed using Chi-square and Fisher’s exact test. Null hypotheses were rejected at a significance level of p≤0.05. Results. The differences in the morphological patterns of primary and recurrent pleomorphic adenomas of the major salivary glands are presented. It was established that in the group of recurrent pleomorphic adenomas, stromal histological subtype (73.3%), partial absence of the outer capsule (85%), myxomatous changes (83.3%), formation of pseudopodia (86.6%), and multifocal growth pattern (73.6%) were more frequently observed, p