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 malignant counterpart of intraductal papilloma has not been described previously. We report one case each of benign and malignant intraductal papillary tumors. The benign tumor occurred in the sublingual gland and was a typical example of intraductal papilloma, with the exception that we found no previously published reports of this type of tumor in this location. The other patient had a left parotid gland tumor that was architecturally similar to the intraductal papilloma, with the addition of cytologic atypia, intraductal extension, microinvasion, and lymph node metastases. This tumor was diagnosed as intraductal papillary adenocarcinoma with an invasive component. Both patients were alive and well without evidence of recurrence 2 years and 6 months (case 1) and 6 years (case 2) after surgery. Immunohistochemical examination revealed that the tumor cells resembled duct luminal cells in both cases. The 2 tumors had different immunoreactivities for carcinoembryonic antigen, p53, and Ki-67. The malignant counterpart of intraductal papilloma should be considered in the differential diagnosis of salivary gland tumors with a predominantly papillary structure, even though this tumor is extremely rare.