Immunohistochemically, the tumor cells located in recognizable duct structures express a phenotype similar to that of the the intercalated duct (positive for keratin, S-100 protein and CD117 (C-kit)) and those around pseudocysts have a phenotype suggestive of myoepithelial cell differentiation (positive for S-100 protein and actin and variable for keratin). This evidence concerns the gene KIT and neoplasm.