Fig. 1.

Immunohistochemistry of α-SMA in CXPA. (A′) and (A″) Intracapsular type, with epithelial component. (A′) Strong expression of α-SMA in the benign myoepithelial cells surrounding the ductal structures of in situ areas. (A″) Presence of myofibroblasts positive for α-SMA close to the capsule. (B) Minimally invasive type, with epithelial component. Desmoplasia is observed in invasion front. (C) and (D) Frankly invasive type, with epithelial component. Strong expression of α-SMA in myofibroblasts revealing intense desmoplasia in septum among blocks of malignant epithelial cells (C) and discrete desmoplasia among small nests of cell (D). (E) Frankly invasive type, with epithelial and myoepithelial components. Expression of α-SMA is seen in a few myofibroblasts in the stroma. Observe the strong expression of α-SMA in malignant myoepithelial cells of ductal structures. (F) Frankly invasive type, with myoepithelial component. Presence of myofibroblasts is very rare in the tumoral stroma. α-SMA is detected in myoepithelial cells and wall vessel