ESR1 and breast fibrocystic disease: Patchy positivity for ER was observed in fibrocystic disease (Fig 2A), fibroadenoma (Fig 2C) and intraductal papilloma (Fig 2E), while expression of HER2/neu was negative in fibrocystic disease (Fig 2B), fibroadenoma (Fig 2C) and intraductal papilloma (Fig 2E).