Benign Neoplasms

BENIGN NEOPLASMS

Fibroadenoma is the most common benign breast tumor in women age <35. It causes a palpable, round, movable, rubbery mass, which on cross-section shows small, cleft-like spaces. Microscopically, the mass shows proliferation of benign stroma, ducts, and lobules

Phyllodes tumor (cystosarcoma phyllodes) usually involves an older patient popula-tion (age 50s) and can be benign or malignant. Local recurrence is common but the incidence of metastasis is low. Microscopically, the mass shows increased stromal cellularity, clefts lined by epithelium, stromal overgrowth, and irregular margins.

Intraductal papilloma commonly presents as a bloody nipple discharge. Microscopi-cally, papilloma causes benign papillary growth within lactiferous ducts or sinuses; the myoepithelial layer is preserved.