Histochemistry: The epithelial component of canalicular adenomas is PAS-positive, diastase sensitive. Immunohistochemistry: The epithelial cells are pankeratin, vimentin and S100 positive. GFAP shows a linear immunoreactivity. p63, calponin, SMA are negative, suggesting absence of myoepithelial differentiation. Recent studies have demonstrated ultrastructural findings which suggest possible origin from intercalated duct cells and striated duct luminal cells. Complete surgical excision is curative.