Breast changes during menstrual cycle, illustration 插畫檔

Comparative illustration showing the physiological evolution of breast tissue across four menstrual cycle stages. During the early follicular phase (days 0-5), acinar epithelial cells appear uniform and lack vacuoles, accompanied by mild stromal oedema. As the cycle progresses through the late follicular (days 6-15) and early luteal phases (days 16-24), progressive alterations in cellular stratification and vacuolisation are observed. By the late luteal phase (days 25-28), acinar epithelial cells exhibit markedly increased vacuolisation and mitotic figures, while apoptotic bodies at the basal layer indicate tissue regression. The outermost basement membrane remains clearly defined, whereas the underlying stroma showing extensive oedema and inflammatory infiltration