Diagnosis: Canalicular adenoma
Normal salivary gland tissue contains acini that drain into intercalated ducts, which drain into intralobular/striated ducts, which then drain into interlobular ducts.
Myoepithelial cells with contractile properties normally underlie the luminal cells of acini, intercalated ducts, and striated ducts.
These cells stain positively for cytokeratin, smooth muscle actin (SMA), and p63.
Pleomorphic adenoma, basal cell adenoma, basal cell adenocarcinoma, and adenoid cystic carcinoma likely arise within intercalated ducts and accordingly contain myoepithelial cells.
Canalicular adenomas do not stain positively for p63, probably because these lesions derive from luminal ductular cells.
