Histologic Changes in Lobules During the Menstrual Cycle (Adapted from Mccarty and Nath (8))

Reff: (8). McCarty KS, Nath M. Breast. In: Sternberg SS, ed. Histology for Pathologists. Philadelphia: Lippincott-Raven; 1997:71–82.

Menstrual Cycle Phase Epithelium Acinar Lumina Intralobular Stroma Early follicular Cells: single cell type (small, polygonal cells with pale eosinophilic cells); myoepithelial cells inconspicuous Orientation: poor Secretion: none Mitoses/apoptosis: rare Largely closed and inapparent Dense, cellular, with plump fibroblasts Late follicular Cells: three cell types, including luminal basophilic cells, intermediate pale cells (as seen in early follicular phase), and myoepithelial cells with clear cytoplasm Orientation: radial around lumen Secretion: none Mitoses/apoptosis: rare Well defined Less cellular and more collagenized than in early luteal phase Early luteal Cells: three cell types, including luminal basophilic cells with minimal apical snouting, intermediate pale cells, and myoepithelial cells with prominent cytoplasmic vacuolization and ballooning Orientation: radial around lumen Secretion: slight Mitoses/apoptosis: rare Open, enlarged compared to follicular phase, with slight secretion Loose Late luteal Cells: three cell types, including luminal basophilic cells with prominent apical snouting, intermediate pale cells and myoepithelial cells with prominent cytoplasmic vacuolization Orientation: radial around lumen Secretion: active apocrine secretion from luminal cells Mitoses/apoptosis: frequent (peak of mitotic activity) Open, with secretion Loose, edematous, congested blood vessels Menstrual Cells: two cell types, including luminal basophilic cells with scant cytoplasm and less apical snouting than in late luteal phase, and myoepithelial cells with extensive cytoplasmic vacuolization Orientation: radial around lumen Secretion: resorbing Mitoses/apoptosis: rare Distended with secretion Dense, cellular