A female is giving a history of smoking 20 cigarettes a day. Which of the following condition is she maximally predisposed to?

Squamous metaplasia of lactiferous ducts( ZUSKA DISEASE ) Smoking is responsible for causing squamous metaplasia of lactiferous ducts. The key feature is keratinizing squamous metaplasia of the nipple ducts. Keratin shed from these cells plugs the ductal system, causing dilation and eventually rupture of the duct. An intense chronic granulomatous inflammatory response develops once keratin spills into the surrounding periductal tissue.