Pleomorphic adenoma of the minor salivary gland with pseudoepitheliomatous hyperplasia of the overlying oral mucosa: report of two cases.

Abstract

Two cases of intra-oral pleomorphic adenoma with marked pseudoepitheliomatous hyperplasia of the overlying oral mucosa are reported. Incisional biopsy specimens, taken a few weeks before surgical excision of the tumor, showed no squamous cell element. Surgically excised specimens revealed pseudoepitheliomatous hyperplasia with hyperortho- and para-keratinization, which extended from overlying oral squamous epithelium, where an incisional biopsy was performed into the deep tumor area. Approximately half of the tumor area in case 1 and one-third in case 2 were occupied by hyperplastic squamous epithelium of the oral mucosa. Although the induction mechanism of such prominent pseudoepitheliomatous hyperplasia of the overlying oral mucosa occupying more than one-third of the tumor area could not be understood, it is thought that surgical injury and/or focal anesthesia during the incisional biopsy played an important role. To the best of our knowledge, these two cases represent the first reported association between benign salivary gland tumor and marked pseudoepitheliomatous hyperplasia of the overlying oral mucosa.