A case of canalicular adenoma arising on the upper lip

Canalicular adenoma is a rare benign tumor that arises in the minor salivary gland. Clinically, it usually presents as an asymptomatic nodule on the upper lip or buccal mucosa. It is necessary to histopathologically differentiate canalicular adenoma from basal cell adenoma and adenoid cystic carcinoma. Canalicular adenoma shows tubular structures composed of 1 or 2 layers of columnar cells and intraluminal hemorrhage. Squamous morales, which seem to represent metaplasia, are a unique finding for this tumor. Immunohistochemical staining is often helpful for the diagnosis of canalicular adenoma, which is positive for S-100 and CK (AE1/3). Herein, we report a case of canalicular adenoma in a 71-year-old man who presented with an asymptomatic nodule on the upper lip. As far as we know, this is the first report of canalicular in Korean Dermatology Journal.