Canalicular adenoma arising in the upper lip: review of the pathological findings

This case report describes a rare case of canalicular adenoma arising in the upper lip of a 61-year-old male patient. Macroscopic examination of the tumor revealed a well-defined, smooth, firm, elastic hard, round nodule with a diameter of 1.0 cm. The cut surface was white. Histopathology showed that the tumor was an encapsulated mass with a complex cellular pattern of anastomosing duct-like or trabecular structures lined by a single layer of tall columnar epithelial cells, which were embedded in a loose, fibrous, and highly vascular connective tissue stroma. The tumor cells were immunoreactive to AE1/AE3, CK19 and S-100, were partially positive for CK7, CK8, GFAP and PCNA, but were negative for SMA, CK13, CK14 and vimentin.