Radial scar (complex sclerosing lesion) is a benign fibroepithelial lesion of the breast consisting of ductular structures radiating around a sclerelastotic central core. It manifests as architectural distortion on mammography and can mimic malignancy. Central lucency (radiolucent center) is a pathognomonic finding — unlike the dense central core in malignant lesions, the center of a radial scar is typically less dense or lucent. This appearance, termed the 'black star sign,' describes a spiculated lesion with a lucent center. The lesion has long spicules and its configuration changes on different projection angles — this variability is not seen in true masses. Lesions larger than 10 mm are termed 'complex sclerosing lesions.' Due to association with atypical ductal hyperplasia, LCIS, or invasive carcinoma, histopathological evaluation is mandatory. Classified as BI-RADS 4 with core/vacuum biopsy indication.
Age Range
40-60
Peak Age
50
Gender
Female predominant
Prevalence
Uncommon
Radial scar develops from fibroelastic proliferation of the terminal ductal lobular unit (TDLU). The central fibroelastotic core consists of collagen and elastin accumulation — ducts in this area are compressed, distorted, and may become obliterated. Ductular and lobular structures around this central fibrous area extend radially and show proliferation (epithelial hyperplasia, adenosis, papillomatosis). The reason it creates architectural distortion on mammography is that this central fibrous core pulls surrounding tissue radially, creating spicule-like structures. The physical basis for central lucency is that despite the central fibrous area containing dense collagen, cellular density is low due to obliteration of ductal structures, allowing X-rays to pass more easily — in invasive carcinomas, dense tumor cells accumulate centrally creating opacification. Projection-dependent configuration change results from the lesion's three-dimensional star shape — spicule distribution varies when viewed from different angles. The carcinogenesis relationship is not definitive, but risk of atypical ductal hyperplasia, LCIS, or low-grade invasive carcinoma (especially tubular carcinoma) developing at the base of a radial scar is increased — likely due to chronic proliferative microenvironment and stromal-epithelial interactions.
Radially extending spicules surrounding a central radiolucent (lucent/black) area on mammography — the center of a spiculated lesion being transparent/dark, unlike invasive carcinoma. No true mass core exists. The 'black star' term refers to the dark (lucent) area at the center of the star-shaped spiculated structure and is contrasted with 'white star' (invasive carcinoma — spiculated mass with dense central core).
Architectural distortion — radially extending spicules with central radiolucent (lucent) area. No mass or minimal central density is present. Spicules are long and thin, appearing more delicate compared to the short, thick spicules of invasive carcinoma. Irregular retraction and distortion of surrounding parenchyma is observed. The lesion is sometimes detected only on a single projection view.
Report Sentence
Architectural distortion is seen in the ___ quadrant of the right/left breast with central lucency (black star sign), consistent with radial scar / complex sclerosing lesion; BI-RADS 4, histopathological evaluation is recommended.
On tomosynthesis (DBT) the central lucent area is more clearly delineated compared to 2D mammography — tissue superimposition is eliminated. Spicule distribution and central lucent area dimensions can be better assessed on different tomosynthesis slices. Lesion configuration varies at different slice levels — reflecting the 3D star morphology. Tomosynthesis has 30-40% higher sensitivity than conventional mammography for radial scar detection.
Report Sentence
On tomosynthesis, architectural distortion with configuration varying across slices is seen at ___ location with central lucent area consistent with radial scar.
On US, radial scar is usually invisible or appears as a very indistinct hypoechoic area — a subtle US finding disproportionate to the prominent architectural distortion on mammography is typical for radial scar. When visible, it appears as a small, irregular, hypoechoic area with posterior shadowing. Sometimes noticed only as a focal change in tissue echogenicity. May not be detectable unless targeted US (directed to mammographic abnormality area) is performed.
Report Sentence
Targeted US to the area of mammographic architectural distortion reveals an indistinctly marginated, mildly hypoechoic area in the ___ quadrant of the right/left breast; core biopsy with histopathological evaluation is recommended.
On MRI, radial scar shows variable enhancement — focal non-mass enhancement (NME) or spiculated mass-type enhancement may be present. Enhancement typically shows Type I (persistent) or Type II (plateau) kinetic curve — Type III (washout) is rare but cannot be excluded. Spiculated structure becomes more apparent on contrast-enhanced T1 sequences. Central fibrous area may not enhance (central lucent area correlation). No significant diffusion restriction on DWI — ADC values are generally in normal range.
Report Sentence
On MRI, a ___ x ___ mm spiculated focal NME/enhancing area with Type I/II kinetic curve is seen in the ___ quadrant of the right/left breast, which may be consistent with radial scar; biopsy evaluation is recommended.
Spicule morphology is better assessed on magnification mammography — in radial scar, spicules are typically long, thin, and uniform in thickness; appearing more delicate compared to the short, thick, irregular spicules of invasive carcinoma. No central mass component or very small. Microcalcifications may be present at spicule tips — in this case, association with atypical hyperplasia or DCIS should be considered.
Report Sentence
On magnification mammography, architectural distortion consisting of long, thin, uniform spicules is seen at ___ location without central mass component; consistent with radial scar.
No significant diffusion restriction on DWI — ADC values are in normal range (generally >1.2 x 10^-3 mm²/s). This finding aids differentiation from invasive carcinomas — invasive carcinomas typically show significant diffusion restriction and low ADC values. However, since some low-grade invasive carcinomas may also show high ADC values, it should not be used as a sole exclusion criterion.
Report Sentence
No significant diffusion restriction is detected in the area of interest on DWI with ADC values in normal range; this finding is consistent with a benign/low-risk lesion.
Criteria
Greatest lesion diameter less than 10 mm. Classified as simple radial scar.
Distinct Features
More difficult to detect on mammography due to small size; often occult. Risk of malignancy association is lower than large lesions but not zero. Biopsy is still recommended.
Criteria
Greatest lesion diameter 10 mm or more. Histologically identical to radial scar but larger in size.
Distinct Features
More prominent architectural distortion on mammography. Risk of malignancy association (atypical hyperplasia, LCIS, invasive carcinoma) is higher than simple radial scar. Surgical excision is preferred in some centers.
Criteria
Detection of atypical ductal hyperplasia (ADH), LCIS, or atypical lobular hyperplasia (ALH) at the base of the radial scar.
Distinct Features
Upgrade risk (benign/atypia on core biopsy → malignancy on excision) is 10-28%. Surgical excision is indicated. No specific difference in mammographic/MRI appearance — histopathological diagnosis.
Distinguishing Feature
Invasive ductal carcinoma appears as a spiculated mass with dense central core ('white star') — different from the central lucency ('black star') of radial scar. Carcinoma spicules are short and thick. Significant diffusion restriction on DWI.
Distinguishing Feature
Invasive lobular carcinoma can also appear as architectural distortion but shows more extensive non-mass enhancement pattern on MRI, Type III (washout) kinetic curve, and low ADC values. Mass component is more prominent on mammography.
Distinguishing Feature
Fat necrosis can also cause architectural distortion but typically has trauma/surgery history, central area of fat density (oil cyst), and characteristic 'eggshell' calcification pattern. T1 hyperintense fat signal on MRI is diagnostic.
Distinguishing Feature
DCIS typically presents as suspicious calcification pattern (fine pleomorphic/fine linear) without architectural distortion. May coexist with radial scar — in this case both distortion and calcification are seen on mammography. Segmental/linear NME is typical on MRI.
Urgency
urgentManagement
surgicalBiopsy
NeededFollow-up
specialist-referralRadial scar mimics malignancy on mammography and histopathological evaluation is mandatory due to carcinoma association. BI-RADS 4 classification is assigned. Tissue sampling with core biopsy or vacuum biopsy is required. Even if benign radial scar is found on core biopsy, some centers prefer surgical excision due to upgrade risk (5-10%) — especially in complex sclerosing lesions (≥10 mm) and when atypia is associated (upgrade risk 10-28%). If atypia is found on biopsy, surgical excision is mandatory.
Radial scar may mimic carcinoma on mammography, biopsy is recommended. If radial scar is diagnosed on core biopsy, excisional biopsy should be discussed due to risk of accompanying atypia/malignancy. Isolated radial scar carries low malignancy risk.