Tubular Adenoma of the Breast

Definition

A benign breast lesion composed of a circumscribed mass of densely packed regular round tubules

Circumscribed mass
- Sharply demarcated but no true capsule
Densely packed, uniform, round tubules
- Two cell layers throughout
  - Lumenal cells epithelial
  - Ablumenal cells myoepithelial
- No cytologic atypia
  - Occasional nucleoli or mitotic figures may be seen
- Cytoplasmic vacuoles not prominent
- Lumenal eosinophilic secretion may be present
Scant stroma
- No compression of ducts
Lactating adenoma may represent the same lesion under different physiologic conditions
- Tubular adenoma has been identified in postpartum biopsies of masses that first presented during pregnancy

Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342