Sclerosing lesions of the breast encompass a spectrum of benign and malignant entities and often pose a diagnostic challenge. Awareness of key morphologic features and pitfalls in the assessment of morphology and immunophenotype is essential to avoid over- or underdiagnosis and ensure optimal clinical management. This review summarizes nonneoplastic sclerosing lesions such as radial scar/complex sclerosing lesion, sclerosing adenosis, sclerosing intraductal papilloma, sclerosing variants of ductal adenoma and nipple adenoma, and fibroadenoma with extensive sclerosis, including their clinical presentation, characteristic morphology, differential diagnostic considerations, appropriate immunohistochemical work-up, when needed, and the clinical significance. In addition, atypical or neoplastic entities (such as atypical ductal hyperplasia, ductal carcinoma in situ, low-grade adenosquamous carcinoma, and fibromatosis-like metaplastic carcinoma) that can involve these sclerosing lesions are also briefly discussed.

OBJECTIVE: Radial sclerosing lesions (RSLs) are benign breast lesions composed of glandular and epithelial proliferations with stellate architecture and fibro-elastotic stroma, which can mimic invasive carcinoma on imaging. Surgical management following a core biopsy diagnosis of RSLs remains controversial.
RESULTS: We retrospectively identified core biopsies with RSLs without atypia who underwent subsequent surgical excision between 2015 and 2021. All core biopsy slides were reviewed to confirm the diagnosis. Imaging was reviewed to determine radiological-pathological concordance. An upgrade was defined as invasive carcinoma or ductal carcinoma in situ (DCIS) in the excision. The final cohort consisted of 130 core biopsies from 124 women (median age = 52 years, range = 27-76). The imaging modality was mammogram in 52 (40%) cases, MRI in 52 (40%) and ultrasound in 26 (20%). One hundred and seven (82%) core biopsies were vacuum-assisted and 23 (18%) were ultrasound-guided without vacuum assistance. The median lesion size on imaging was 9 mm (range = 2-41). Overall, two (1%) cases were upgraded at excision, including one microinvasive lobular carcinoma and one 2 mm focus of invasive mammary carcinoma with associated DCIS. In both cases, the upgraded foci of carcinoma were not closely associated with the biopsy site and were considered incidental upgrades.
CONCLUSIONS: This study adds to the body of literature supporting observation, rather than routine excision of radial sclerosing lesions without atypia.

Complex sclerosing lesion (CSL)/radial scar of breast is a benign entity that can pose a diagnostic challenge due to resemblance to breast carcinoma on imaging. Hamartoma are uncommon benign tumors, composed of disorganized mixture of glandular, fibrous, and adipose tissues, which can exhibit classical imaging characteristics. Here we describe a case of concomitant CSL and hamartoma in left beast, of which CSL presented as suspicious mass on imaging but was ultimately confirmed to be benign on histopathology with 4 years of documented stability.

OBJECTIVE: To determine the best management option (surgical excision versus imaging surveillance) following the diagnosis of pure radial scars (RSs) and RSs with associated additional high-risk lesions (HRLs) encountered on percutaneous core-needle breast biopsy.
METHODS: An IRB-approved retrospective review of the breast imaging reporting system database was performed to identify all cases of pure RS alone or RS plus an additional HRL (papilloma, atypia, lobular neoplasia) diagnosed on core-needle biopsy, from 2007 to 2016, at four breast centers in our institution. Cases with associated malignancy, discordant radiologic-pathologic results, or those lost to follow-up were excluded. The remaining cases were evaluated to determine results of either subsequent surgical excision or long-term follow-up imaging (minimum of two years). Additional data recorded included clinical presentation, breast density, personal and family history of breast cancer, lesion imaging characteristics, and biopsy method.
RESULTS: The study cohort included 111 patients with 111 lesions: 56.8% (63/111) with RS alone (pure) and 43.2% (48/111) with RS plus additional HRL(s). Out of the 63 radiologic-pathologic concordant pure RSs, there were no upgrades to malignancy in 51 subsequent surgical excisions or 12 long-term surveillance cases (0/63, 0%). Out of the 48 RSs plus additional HRL(s), there were 2 upgrades to malignancy (2/48, 4.2%).
CONCLUSIONS: Cases of radiologic-pathologic concordant pure RS diagnosed at core-needle biopsy do not require surgical excision. On the other hand, surgical excision should be considered for RS plus additional HRLs diagnosed at core-needle biopsy.

UNASSIGNED: A radial scar (RS) is a benign breast lesion (BBL) that has an obscure etiology. RS is easily confused with breast carcinoma and therefore correct identification radiologically and pathologically is important. The aim of this study was to determine the incidence of atypical lesions by evaluating RS detected with BBL and to investigate whether atypia and RS are related to their characteristics.
UNASSIGNED: A total of 1.370 patients with a diagnosis of BBL postoperatively in a single department were analyzed retrospectively. Forty-six confirmed RS/complex sclerosing lesion (CSL) cases were selected. The demographic and clinical characteristics of the patients and the relationship between RS and other BBL were evaluated. In addition, the relationship between RS/CSL and the presence of atypia was interpreted.
UNASSIGNED: The mean age was 45.17±8.72 years. Spiculated lesion (34.8%) on mammography and microcalcification (37%) on histopathological examination were the most common features. The most common BBL accompanying RS/CSL was adenosis. Atypical epithelial hyperplasia (AEH) was presented in 15 (32.6%) of those diagnosed with RS. Although all patients were benign, the frequency of AEH accompanying RS was found to be significantly higher. The mean size of RS was 10.8±8.4 mm (2-30 mm). The size of RS/CSL was not significantly associated with atypia.
UNASSIGNED: RS/CSLs usually present as suspicious lesions that must be distinguished radiologically from malignancy. However RS, which can be present with malign breast lesions, can be also seen with all BBL. Therefore, core biopsy and/or excisional biopsy continue to be important for definitive histopathological diagnosis.

We assessed the cancer upstage rate of Radial Scars (RS), and Complex Sclerosing Lesions (CSL), and risk-stratified lesions based on radiological and pathological features.
Characteristics of RS/CSL treated from 2013 to 2018 were examined for features associated with cancer.
78 RS/CSL were found on core needle biopsy (CNB) and surgically excised. 9 (11.5%) lesions were upstaged. Upstaged patients were older (66 vs 51, p = 0.033). More upstaged lesions were accompanied by a mass on both mammography (87.5% vs. 30.0%, p = 0.005) and ultrasound (100.0% vs. 62.8%, p = 0.043). 20.5% of lesions biopsied under ultrasound guidance with small needles (14-18G) were upstaged, but no lesions biopsied under stereotactic guidance with large needles (9-12 G) with vacuum assistance were upstaged (p = 0.009).
Excision of RS/CSL seen on CNB is warranted, especially if the patient is older, the CNB is performed under ultrasound guidance with small needles, or if a mass is present on imaging.

To describe the magnetic resonance characteristics of radial scars/complex sclerosing lesions (RS/CSL) of the breast using the current BI-RADS lexicon. To investigate the value of diffusion weighted imaging to predict malignancy.
From 2010 to 2017, we have found 25 women with architectural distortion at mammography who underwent surgical resection with a final hystopathologic report of RS/CSL. For the description of MRI findings, we adhered to BI-RADS classification (5th edition).
The final pathological diagnosis was: \"pure\" RS/CSL in 7 cases (28%), RS/CSL with associated high risk lesions in 12 (48%) and 6 cases (24%) were associated with malignancy. Magnetic resonance findings: four of 25 negative or focus. Five of 25 mass enhancement: irregular, non circumscribed spiculated mass with heterogeneous or rim enhancement and most with type II curves. Sixteen of 25 non mass enhancement: focal or linear distribution and heterogeneous internal enhancement most with type I curves. Six of 25 had cancer associated with the complex sclerosing lesion. All six showed non-mass enhancement. Two cases with invasive breast carcinoma had ADC values under 1.15 x10-3 mm/s while most of the rest had the values above.
Most RS/CSL showed enhancement at MR. The predominant pattern was a non-mass, focal, heterogeneous internal enhancement with type 1 curves. All cases with associated cancer showed non mass enhancement. Invasive breast cancers had ADC values < 1.15 10-3 s/mm2.

OBJECTIVE: Radial scars and complex sclerosing lesions of the breast are part of a group of \"indeterminate\" breast lesions, which are excised due to risk of coexistent carcinoma. The aim of this study was to assess rate of upgrade of these lesions to invasive and in situ carcinoma and to quantify the risk of development of subsequent cancer in women diagnosed with these lesions.
METHODS: A retrospective review of a prospectively maintained breast screening database was performed. All patients with radial scar identified at either core biopsy or final excision biopsy between January 2006 and July 2012 were identified. Full pathological reports for both core biopsy and final excision biopsy were reviewed. Patient outcomes were followed for a mean of 117.1 months.
RESULTS: Of 451 B3 biopsies performed at our screening unit, 95 (22%) were found to have a radial scar or complex sclerosing lesion (CSL) on core needle biopsy. Within this group, 77 had no atypia on CNB, with 7 (9%) upgraded to invasive/in situ carcinoma on final excision. Of nine with definite atypia on CNB, 3 (33%) were upgraded. In those patients without atypia or malignancy on final excision, 7.5% developed cancer during 10-year follow-up.
CONCLUSIONS: Patients with radial scar with atypia have a higher risk of upgrade to malignancy. Further research is needed to identify which patients may safely avoid excision of radial scar. Patients with a diagnosis of radial scar on CNB are at increased subsequent risk of breast cancer and may benefit from additional screening.

UNASSIGNED: To review breast magnetic resonance imaging (MRI) features of radial scar (RS) with and without associated atypia/malignancy.
UNASSIGNED: Twenty-eight (mean age 56.8) patients diagnosed with 30 biopsy-proven RS (n = 25, ultrasound-guided 14-gauge, n = 5, stereotactically guided 9-gauge) subsequently underwent breast MRI followed by surgery. Magnetic resonance imaging protocol included axial T1, axial fat sat T2, and postgadolinium in axial and sagittal planes. Two radiologists reviewed the mammographic and MRI findings in consensus according to the Breast Imaging Reporting and Data System lexicon.
UNASSIGNED: Of the 30 RSs excised surgically, 14 (14/30, 47.7%) were not associated with atypia/malignancy while atypia/malignancy was found in 16 (16/30, 53.3%) RSs. Three (3/30, 10%) RS lesions did not enhance on dynamic MR. Mean lesion size on MRI was 1.4 cm (range, 0.5-5 cm). Seventeen (17/30, 56.7%) lesions presented as nonmass enhancement and 9 (9/30, 30%) as masses. Nonmass lesions showed focal distribution (13/17, 76.5%) and heterogeneous enhancement (15/17, 88.2%). Masses showed irregular shape and margins (6/9, 67%) and heterogeneous enhancement (8/9, 89%). Multivariate analysis did not show any significant difference in MRI presentation between RS only and RS associated with atypia/malignancy.
UNASSIGNED: Breast MRI does not help differentiate between RS with or without associated atypia/malignancy.

OBJECTIVE: Management of the radial scar (RS)/complex sclerosing lesion (CSL) diagnosed by core needle biopsy (CNB) in breast cancer screening population (BCSP) is controversial due to its intrinsic malignant potential. We aimed to determine (i) the rate of upgrade of the RS/CSL to malignant lesions and (ii) radiological characteristics and CNB histopathological findings of the lesions related to the upgrade of the RS/CSL to malignant lesions after surgical excision in our BCSP.
METHODS: Database of Slovenian National Breast Cancer Screening Program was checked for terms RS/CSL in all patients who underwent CNB in the period 2008-2018. The ratios of upgrade from CNB RS/SCL to malignant lesions after surgical excision were calculated with specific interest to the radiological characteristics and the CNB patohistologically findings of the lesions.
RESULTS: Of 162 patients with diagnosis of RS/CSL on the CNB, 121/156 (78%) cases underwent surgical excision. 6 of 121 (5%) cases were upgraded to a malignant diagnosis in surgical specimen, 3 cases of invasive carcinoma and 3 cases of DCIS, respectively. Five of the upgraded cases (5/6, 83.3%) showed atypical epithelial proliferative lesions (AEPL) on CNB. In one upgraded case without AEPL the lesion presented as 33 mm architectural distortion with microcalcifications on the mammogram.
CONCLUSIONS: In BCSP setting RS/CSL without AEPL/papilloma and those measuring less than 2 cm in the largest diameter can be followed radiologically. Increasing the number of cores and adequate sampling of the periphery and the centre of the RS/CSL improves the pick-up rate of associated atypia/malignancy.