Breast fibroadenoma, light micrograph. A breast fibroadenoma is a benign tumour, frequently nodular and encapsulated, that consist of a proliferation of both stromal and epithelial components. The fibroadenoma intracanalicular can be arranged in two growth patterns, often found in the same tumour: intracanalicular (stromal proliferation predominates and compresses the ducts, which are irregular, reduced to slits) appearing as elongated epithelial duct structures situated within a loose, myxoid stroma, and pericanalicular (fibrous stroma proliferates around the ductal spaces, so that they remain round or oval, on cross section) visible on the right side of the image. |