Intraductal papillary tumors of the major salivary glands - Case reports of benign and malignant variants

Intraductal papilloma is an extremely rare benign salivary gland tumor that occurs most commonly in the minor salivary glands. To our knowledge, a mal ignant counterpart of intraductal papilloma has not been described previous ly. We report one case each of benign and malignant intraductal papillary t umors. The benign tumor occurred in the sublingual gland and was a typical example of intraductal papilloma, with the exception that we found no previ ously published reports of this type of tumor in this location. The other p atient had a left parotid gland tumor that was architecturally similar to t he intraductal papilloma, with the addition of cytologic atypia, intraducta l extension, microinvasion, and lymph node metastases. This tumor was diagn osed as intraductal papillary adenocarcinoma with an invasive component. Bo th patients were alive and well without evidence of recurrence 2 years and 6 months (case 1) and 6 years (case 2) after surgery. Immunohistochemical e xamination revealed that the tumor cells resembled duct luminal cells in bo th cases. The 2 tumors had different immunoreactivities for carcinoembryoni c antigen, p53, and Ki-67. The malignant counterpart of intraductal papillo ma should be considered in the differential diagnosis of salivary gland tum ors with a predominantly papillary structure, even though this tumor is ext remely rare.