Figure 1.

Benign/low grade malignant salivary gland-like tumours with myoepithelial differentiation. (A) Mammary pleomorphic adenoma has circumscribed margins and shows a central area of cartilaginous tissue; (B) medium power magnification disclosing glandular structures immersed in a myxoid stroma. (C) Adenoid cystic carcinoma (ACC) of the breast showing solid and cribriform architecture; inset, breast ACC is composed of basaloid cells that outline spaces containing basal-like material and of eosinophilic cells lining true glandular lumina; (D) staining for smooth muscle actin (SMA) demonstrates myoepithelial cells. (E) Syringomatous carcinoma/low grade adenosquamous carcinoma (SyC/LGASC) is composed of angulated glands located in desmoplastic stroma; (F) SyC squamous differentiation is frequent and contains high molecular weight keratin. (G) Breast adenomyoepithelioma (AME): glandular structures are formed by an inner layer of epithelial cells with eosinophilic cytoplasm and by an outer layer of myoepithelial cells with clear cytoplasm; (H) staining for calponin demonstrates myoepithelial cells in breast AME.