This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Breast, Subject name: Pathology
A female is giving a history of smoking 20 cigarettes a day. Which of the following condition is she maximally predisposed to? 
Select and explain. 
A. Acute mastitis, B. Granulomatous mastitis, C. Fat necrosis, D. Squamous metaplasia of lactiferous ducts
D: Squamous metaplasia of lactiferous ducts
Answer: D: Squamous metaplasia of lactiferous ducts 
Explanation: 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.