Radial Scar of the Breast

Definition

• A benign breast lesion with a stellate architecture that may simulate invasive carcinoma mammographically, clinically, grossly and microscopically

Alternate / historical names

• Sclerosing papilloma
• Sclerosing duct lesion

Diagnostic Criteria

• Stellate architecture
  • Extensive elastosis common
• No invasion of fat by naked tubules
• Ducts irregular, lined by two or more cells
  • Ducts frequently demonstrate fibrocystic change
  • Epithelial cells may show usual hyperplasia
  • Myoepithelial layer is present
  • May infrequently be associated with or contain atypical hyperplasia or ductal carcinoma in situ
  • Columnar cell change and flat epithelial atypia may also be present

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

Original posting: May 1, 2006

Supplemental studies

Immunohistology

• The tubules of radial scar contain a layer of myoepithelial cells
• Demonstration of myoepithelial cells can confirm the in situ or benign nature of a process while their absence supports invasion
  • A variety of markers have been used for myoepithelial cells
  • We prefer to use both p63 and calponin on problematic cases

Marker	Sensitivity	Specificity
Calponin	Excellent	Very good
p63	Excellent	Excellent
Smooth muscle myosin heavy chain	Good	Excellent
CD10 (CALLA)	Good	Good
High molecular weight cytokeratin	Very good	Poor
Maspin	Good	Poor
S100	Good	Very poor
Actin	Good	Very poor

Differential Diagnosis

• Tubular carcinoma
• Infiltrating ductal carcinoma
• Sclerosing adenosis, ductal adenoma, nipple adenoma

Infiltrating Ductal Carcinoma	Radial Scar
Cells may show various levels of atypia	Cytologically bland cells
No myoepithelial cells	Myoepithelial cells present
Frequent infiltration of fat by naked tubules	No bare infiltration of fat
May show various infiltrative patterns	Stellate configuration

Radial Scar, Sclerosing Adenosis, Ductal Adenoma and Nipple Adenoma

• May be considered a spectrum of lesions differing in location and predominant pattern
• All are benign

Clinical

• Radial scar (in the absence of associated DCIS) is considered a marker of increased risk of carcinoma rather than a precursor lesion
  • In an excisional biopsy, margins are not relevant if it is the only lesion

Relative risk for development of invasive breast carcinoma

• No increased risk
  • Non-proliferative fibrocystic change
  • Fibroadenoma
  • Solitary papilloma
• Slightly increased risk (1.5 to 2 times)
  • Proliferative fibrocystic change
  • Usual ductal hyperplasia
  • Sclerosing adenosis (florid)
  • Radial scar
  • Complex fibroadenoma (approximately 3 times risk)
• Moderately increased risk (4 to 5 times)
  • Atypical ductal hyperplasia (no family history)
  • Atypical lobular hyperplasia
• High risk (8 to 10 times)
  • Ductal carcinoma in situ, low grade
  • Lobular carcinoma in situ
  • Atypical ductal hyperplasia, if history of carcinoma in primary relatives
• Very high risk (precise level not known)
  • Ductal carcinoma in situ, high grade

Bibliography

• Andersen JA, Carter D, Linell F. A symposium on sclerosing duct lesions of the breast. Pathol Annu. 1986;21 Pt 2:145-79.
• Andersen JA, Gram JB. Radial scar in the female breast. A long-term follow-up study of 32 cases. Cancer. 1984 Jun 1;53(11):2557-60.
• Anderson TJ, Battersby S. Radial scars of benign and malignant breasts: comparative features and significance. J Pathol. 1985 Sep;147(1):23-32.
• Sloane JP, Mayers MM. Carcinoma and atypical hyperplasia in radial scars and complex sclerosing lesions: importance of lesion size and patient age. Histopathology. 1993 Sep;23(3):225-31.
• Jacobs TW, Byrne C, Colditz G, Connolly JL, Schnitt SJ. Radial scars in benign breast-biopsy specimens and the risk of breast cancer. N Engl J Med. 1999 Feb 11;340(6):430-6.