Tubular Adenoma of the Breast

Definition

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

Diagnostic Criteria

• 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

Original posting: May 15, 2006

Supplemental studies

Immunohistology

• Lumenal cells ER positive
• Ablumenal cells positive for myoepithelial markers
  • Calponin, p63, smooth muscle actin positive
  • S100 positive

Differential Diagnosis

• Lactating adenoma
• Microglandular adenosis
• Sclerosing adenosis
• Fibroadenoma
• Ductal adenoma
• Nipple adenoma
• Tubular carcinoma
• Tubular adenosis

Lactating Adenoma	Tubular Adenoma
Prominent lactational change	Lumenal secretion may be present, but cytoplasmic vacuoles lacking

These may represent the same lesion under different physiologic conditions

Microglandular Adenosis	Tubular Adenoma
Poorly circumscribed pattern	Circumscribed
Surrounds normal elements	Mass displaces normal elements
No myoepithelial cell layer	Myoepithelial cell layer present
Haphazardly scattered tubules	Densely packed tubules
Abundant fibrous or fatty stroma	Scant stroma

Sclerosing Adenosis	Tubular Adenoma
Localized but not sharply circumscribed	Sharply circumscribed
Distorted, compressed ducts	Uniform patent ducts
Cellular stroma	Scant stroma

Adenomatous Transformation of Fibroadenoma	Tubular Adenoma
Areas of typical fibroadenoma stroma	Scant stroma
Variable tubules	Uniform tubules

Areas typical of tubular adenoma may be found within fibroadenomas

Ductal Adenoma	Tubular Adenoma
Frequent prominent sclerosing stroma	Scant stroma
Fibrous capsule	No capsule
Localized but not completely circumscribed	Completely sharply circumscribed
Papillomatosis or adenomatosis with variable small glands	Uniform glands

Nipple Adenoma	Tubular Adenoma
Frequent prominent sclerosing stroma	Scant stroma
Localized but not completely circumscribed	Completely sharply circumscribed
Papillomatosis or adenomatosis with variable small glands	Uniform glands

Tubular Carcinoma	Tubular Adenoma
Stellate infiltrative pattern	Circumscribed
No myoepithelial layer	Myoepithelial cells present

These are similar in name only

Tubular Adenosis	Tubular Adenoma
Diffuse, infiltrative	Circumscribed
Surrounds normal elements	Mass displaces normal elements
Haphazardly scattered tubules	Densely packed tubules
Abundant fibrous or fatty stroma	Scant stroma

These are similar in name only

Clinical

• Most cases occur between 15-49 years of age
• Rare lesion
• No association with pregnancy or oral contraceptive use
  • Lactating adenoma may represent the same lesion under different physiologic conditions
• No recurrences reported
• No evidence for increased risk of carcinoma

Lists

Breast Adenomas (not all are true adenomas)

• Apocrine adenoma
• Ductal adenoma
• Fibroadenoma
• Infiltrating syringomatous adenoma
• Juvenile fibroadenoma
• Nipple adenoma
• Lactating adenoma
• Pleomorphic adenoma
• Tubular adenoma

Bibliography

• Maiorano E, Albrizio M. Tubular adenoma of the breast: an immunohistochemical study of ten cases. Pathol Res Pract. 1995 Dec;191(12):1222-30.
• O'Hara MF, Page DL. Adenomas of the breast and ectopic breast under lactational influences. Hum Pathol. 1985 Jul;16(7):707-12.
• Hertel BF, Zaloudek C, Kempson RL. Breast adenomas. Cancer. 1976 Jun;37(6):2891-905.