Immunohistochemical analysis of salivary gland canalicular adenoma

Canalicular adenoma is a newly recognized salivary gland adenoma that may be confused with malignant salivary gland tumors. To better characterize this neoplasm, six examples were investigated with a panel of immunohistochemistry antibodies including anti-keratin (AE1/AE3), anti-epithelial membrane antigen, anti-carcinoembryonic antigen, anti-vimentin, anti-S-100, anti-muscle specific actin, and anti-glial fibrillary acid protein. All canalicular adenomas stained in a similar fashion showing positive staining with anti-keratin, anti-vimentin, and anti-S-100 (6 of 6 cases each). Rare focal staining with anti-epithelial membrane antigen and anti-glial fibrillary acid protein was noted (1 of 6 cases each). This immunohistochemistry staining pattern was compared with those of ameloblastoma, polymorphous low-grade adenocarcinoma, and adenoid cystic carcinoma. Immunohistochemistry may be useful in the distinction of canalicular adenoma from other salivary gland tumors.