Sialadenoma papilliferum of a minor salivary gland with transformation to mucoepidermoid carcinoma.

Sialadenoma papilliferum (SP) is a rare benign tumor usually occurring in the minor salivary glands. Only two cases of malignant transformation of SP and an occasional case of dysplasia in SP have been reported in the literature till now. We report a case of SP of a minor salivary gland in a middle-aged male where the exophytic component retained the histomorphological features of SP while the endophytic component displayed characteristics of a mucoepidermoid carcinoma. Malignant change in sialadenoma papilliferum is an extremely rare phenomenon that requires further research and documentation. Careful evaluation of morphologic features and reporting of more such cases is required to delineate the clinical behavior of this unusual tumor.