A: Flat proliferation with marked nuclear atypia – flat lesion shows prominent nucleoli, irregular nuclear outlines and increased nuclear to cytoplasmic ratio (H&E, 400X); B: Benign without atypia – columnar cell changes with prominent myoepithelial cell layer (H&E, 200X); C, D: Focal atypical ductal hyperplasia (ADH) – demonstrating a spectrum of architectural complexity ranging from minimal (C, H&E, 200X) to more developed ADH (D, H&E, 400X)