Radial scars of benign and malignant breasts: comparative features and significance

Overdiagnosis of breast malignancy: Azzopardi's Problems in Breast Pathology revisited, Part I

Dr. John G. Azzopardi's textbook Problems in Breast Pathology is a critical work for breast pathologists. His observations on over- and underdiagnosis of breast malignancy are summarized in two chapters which are highly educational for everyday practice to reach an accurate diagnosis. Almost five decades later, his observations are still valid, and the same problems persist. In two separate reviews, we revisit these chapters and discuss these diagnostic challenges with an updated perspective and include developments (most importantly immunohistochemistry) in the field since then. In part I, lesions which may be overdiagnosed as malignancy are discussed, including those that were covered in Dr. Azzopardi's textbook (mainly sclerosing adenosis and radial scar) and some others that exert challenges on the pathologist. In part II, we will cover underdiagnosis of breast malignancy.

Significance of adenosquamous proliferation in breast lesions

Adenosquamous proliferation (ASP), characterised by ductal structures with a dual glandular and squamous phenotype within desmoplastic stroma, is essentially a hallmark of various sclerosing lesions of the breast (SL) and breast lesions with sclerosis (BLWS), not including sclerosing adenosis. In radial scar/complex sclerosing lesion (RS/CSL), clonality has been previously demonstrated in microdissected ASP. SL/BLWS encompass a diverse range of pathological entities that historically have an equally diverse list of names, often for histologically alike or identical lesions at different anatomical locations. In common they are comprised of one or more components of fibrocystic or proliferative breast disease and papillomata, which become distorted and even obliterated by a sclerosing process that appears to be associated with and/or secondary to ASP, which in an individual lesion may be inconspicuous at the time of biopsy. The histological overlap of various SL/BLWS with RS/CSL, in which a nidus containing ASP is pathognomonic of early lesions, also supports a common element of ASP across various SL/BLWS. SL/BLWS show an interesting association with low-grade metaplastic carcinoma, particularly low-grade adenosquamous carcinoma (LGASC) with which, they appear to form a histological and possible biological spectrum because ASP and LGASC share similar histological and immunophenotypical characteristics. The presentation of ASP in various SL/BLWS will be discussed.

Core Needle Biopsy of the Breast: An Evaluation of Contemporary Data

Benign and atypical lesions associated with breast cancer risk are often encountered in core needle biopsies (CNBs) of the breast. For these lesions, the rate of "upgrade" to carcinoma in excision specimens varies widely in the literature. Many CNB studies are limited by a lack of radiological-pathological correlation, consistent criteria for excision, and clinical follow-up for patients who forego excision. This article highlights contemporary diagnostic criteria and outcome data that would support an evidence-based approach to the management of these nonmalignant lesions of the breast diagnosed on CNB.

Radial Scars of the Breast Encountered at Core Biopsy: Review of Histologic, Imaging, and Management Considerations

OBJECTIVE

The purposes of this article are to place the controversy over the management of radial scars diagnosed at core biopsy in perspective and to define reasonable management options.

CONCLUSION

The management of radial scars after image-guided core biopsy of the breast for diagnosis remains controversial. Although current literature suggests no premalignant potential of these lesions, it does not fully explain the small but real percentage of these lesions that are upgraded to malignancy after surgical excision. This upgrade phenomenon is probably best explained by core biopsy sampling error. A recommendation minimizing this possibility based on lesion size seems reasonable.

Next generation sequencing of the nidus of early (adenosquamous proliferation rich) radial sclerosing lesions of the breast reveals evidence for a neoplastic precursor lesion

We sought to determine if adenosquamous proliferation of early cellular radial sclerosing lesions of the breast harbours hot spot mutations and to help clarify its relationship to low‐grade adenosquamous carcinoma as a potential form of early neoplasia. Four low‐grade adenosquamous carcinomas, early radial sclerosing lesions from 13 individuals, and 4 benign proliferative breast lesions were microdissected and assessed with a 50‐gene Hot‐spot cancer panel. Early radial sclerosing lesions were selectively microdissected concentrating on their adenosquamous proliferation (nidus). Hot spot mutations in PIK3CA were detected in ten (77% of) radial sclerosing lesions, in one low‐grade adenosquamous carcinoma, and in usual ductal hyperplasia and apocrine adenosis. Over three quarters of individuals with cellular (adenosquamous proliferation rich) early radial sclerosing lesions tested harboured somatic mutations in PIK3CA suggesting that adenosquamous proliferation is a clonal lesion. Its relationship to low‐grade adenosquamous carcinoma remains unclear in view of the small sample size and unmatched radial sclerosing lesions and low‐grade adenosquamous carcinomas.

Small Glandular Proliferations of the Breast With Absent or Attenuated Myoepithelial Reactivity by Immunohistochemistry: A Review Focusing on the Differential Diagnosis and Interpretative Pitfalls

CONTEXT

-Small glandular proliferations of the breast encompass a variety of benign, atypical, and malignant lesions that show some overlapping morphologic features. Myoepithelial stains are frequently used in the workup of these lesions in order to rule out or establish a diagnosis of invasive carcinoma. Some benign lesions show absent or diminished myoepithelial staining, and may represent an interpretative pitfall, particularly in small core biopsy samples.

OBJECTIVE

-To review small glandular proliferations of the breast that show absent or diminished staining with myoepithelial immunohistochemical markers.

DATA SOURCES

-The study comprised a review of published literature and clinical case material.

CONCLUSIONS

-The interpretation of myoepithelial stains in small glandular proliferations of the breast can, on some occasions, represent a challenge in diagnosing these lesions. Recognition of the key histopathologic features and immunohistochemical staining patterns of the entities in the differential diagnosis is crucial in their workup.

Radial scars diagnosed on breast core biopsy: Frequency of atypia and carcinoma on excision and implications for management

AIMS

The risk of finding carcinoma in excisions following a core needle biopsy diagnosis of radial scar is not well defined and clinical management is variable. The aim of this study is to determine the frequency of high-risk lesions, ductal carcinoma in situ, and invasive carcinoma in excisions following a core biopsy diagnosis of radial scar.

METHODS AND RESULTS

Dedicated breast pathologists and radiologists correlated the histologic and radiologic findings and categorized radial scars as the target lesion or an incidental finding. High-risk lesions were defined as atypical hyperplasia or classical lobular carcinoma in situ. Of the 79 radial scars identified over a 14-year period, 22 were associated with atypia or carcinoma in the core biopsy. Thirty-seven (37) of the 57 benign radial scars underwent excision with benign findings in 30 (81%), high-risk lesions in six (16%), and flat epithelial atypia in one (3%). There were no upgrades to carcinoma. One patient with a benign radial scar developed a 3-mm focus of intermediate-grade estrogen receptor-positive ductal carcinoma in situ in the same quadrant of the ipsilateral breast 72 months after excision. One patient with an incidental un-excised benign radial scar was diagnosed with ductal carcinoma in situ at a separate site of suspicious calcifications.

CONCLUSIONS

In this series, none of the benign radial scars was upgraded to carcinoma. Radial scar was the targeted lesion in all cases with high-risk lesions on excision. Surgical excision may not be mandatory for patients with benign incidental radial scars on core biopsy.

Adenosquamous proliferation of the breast and low grade adenosquamous carcinoma: a common precursor of an uncommon cancer?

Low grade adenosquamous carcinoma (LGASC) is rare but commonly reported to arise in association with benign proliferative and sclerosing breast lesions which themselves may show associated sclerosing or 'adenosquamous proliferation' (ASP) resembling LGASC, but are often derided as reactive mimics or attributed to earlier biopsy. Among other benign lesions, radial sclerosing lesion (RSL) may be associated with LGASC, yet attention is typically focused on its relationship to more common forms of mammary carcinoma. This study aimed to assess the presence and extent of ASP in the context of RSL in a small cohort of 20 cases and its similarity to LGASC.Twenty consecutive breast excisions that had a principal or incidental diagnosis of RSL were reviewed. RSLs that displayed foci of ASP were further examined with immunohistochemical markers for p63, calponin, cytokeratin 5/6, oestrogen and progesterone receptors.Sixty percent of excisions contained ASP either associated with a RSL or a concurrent papilloma, which morphologically and immunohistochemically were indistinguishable from the neoplastic ducts of LGASC. RSL with and without ASP broadly corresponded to accepted definitions for 'early' and 'late' lesions, respectively. ASP corresponded to the characteristic compact branching ducts of the core or nidus of a RSL.The morphological and immunophenotypic similarity of the ASP found in RSL and papillomata to LGASC warrants serious consideration that they are a potential precursor to LGASC, which may most commonly involute given the rarity of clinically apparent LGASC. Further study including micro-dissection of foci of ASP to compare its molecular genetic profile to that of LGASC is required.

Multifocal fibrosing thyroiditis and its association with papillary thyroid carcinoma using BRAF pyrosequencing

Multifocal fibrosing thyroiditis (MFT) is characterized by numerous foci of fibrosis in a stellate configuration with fibroelastotic and fibroblastic centers entrapping epithelial structures. MFT has been proposed as a risk factor for papillary thyroid carcinoma (PTC) development. We attempted to identify whether MFT showed such molecular changes and could possibly be related to PTC. We identified seven cases of PTC with MFT in our institutional pathology database and personal consult service of one of the authors (VAL) for the years 1999 to 2012. Areas of PTC, MFT, and normal tissue were selected for BRAF analysis. Macro-dissection, DNA extraction and PCR amplification, and pyrosequencing were performed to detect BRAF mutations in codon 600. All of the MFT lesions and normal thyroid tissue were negative for BRAF mutations. Of the seven PTCs analyzed, five (71 %) were negative for BRAF mutations, while two cases were positive. In our study, none of the MFT lesions harbored BRAF mutations, whereas 29 % (two of seven) PTCs in the same gland were positive. Hence, in this small study, we found no evidence that the MFT lesion is a direct precursor to PTC. It is likely an incidental bystander in the process and a reflection of the background thyroiditis.

Frequent PIK3CA mutations in radial scars

Radial scars are breast lesions of uncertain pathogenesis that are associated with a 2-fold increased risk of breast cancer compared with that in controls. Activating point mutations in PIK3CA are found in 25% to 30% of invasive breast cancers; however, they have not previously been investigated in radial scars. We sought to evaluate radial scars for known activating point mutations commonly seen in invasive breast cancer. Sixteen surgical cases containing 22 radial scars were identified from pathology archives. Lesional tissue was macrodissected from unstained paraffin sections; genomic DNA was then extracted and screened for a panel of known hotspot mutations using polymerase chain reaction and mass spectroscopy analysis. Of the 22 radial scars, 14 (63.6%) had PIK3CA mutations (10 with H1047R mutations, 2 G1049R mutations, 1 E542K, 1 E545K). The remaining 8 lesions were wild type for all of the screened genes. Of the radial scars without epithelial atypia, 9/16 (56.3%) had PIK3CA mutations; furthermore, 5/6 (83.3%) radial scars with atypia had mutations detected. In this study, the frequency of PIK3CA mutations was notably higher than the 25% to 30% mutation frequency of invasive breast cancer. This finding raises interesting questions as to the role of PIK3CA mutations in breast cancer development. Additional larger studies are indicated to confirm and extend these observations in understanding the pathogenesis of radial scars and their relationship to breast cancer.

Breast cancer precursors revisited: molecular features and progression pathways

Increasingly more coherent data on the molecular characteristics of benign breast lesions and breast cancer precursors have led to the delineation of new multistep pathways of breast cancer progression through genotypic-phenotypic correlations. It has become apparent that oestrogen receptor (ER)-positive and -negative breast lesions are fundamentally distinct diseases. Within the ER-positive group, histological grade is strongly associated with the number and complexity of genetic abnormalities in breast cancer cells. Genomic analyses of high-grade ER-positive breast cancers have revealed that a substantial proportion of these tumours harbour the characteristic genetic aberrations found in low-grade ER-positive disease, suggesting that at least a subgroup of high-grade ER-positive breast cancers may originate from low-grade lesions. The ER-negative group is more complex and heterogeneous, comprising distinct molecular entities, including basal-like, HER2 and molecular apocrine lesions. Importantly, the type and pattern of genetic aberrations found in ER-negative cancers differ from those of ER-positive disease. Here, we review the available molecular data on breast cancer risk indicator and precursor lesions, the putative mechanisms of progression from in situ to invasive disease, and propose a revised model of breast cancer evolution based on the molecular characteristics of distinct subtypes of in situ and invasive breast cancers.

Pseudoneoplastic lesions: general considerations

Pseudoneoplastic lesions ("pseudotumors") can be seen in virtually all anatomic locations. Some organ sites, such as the lungs and skin, are overrepresented for unknown reasons, and the histologic images seen in pseudoneoplastic lesions are partially overlapping in disparate locations. More than occasionally, the degree of histologic likeness to true neoplasms-often malignant ones-is striking. This overview outlines the spectrum of pseudoneoplastic lesions and divides them into etiologic categories, including reparative, developmental, functional (usually endocrine), iatrogenic, infectious, and idiopathic. Side-by-side pictorial comparisons of selected pseudoneoplastic lesions and their neoplastic mimics are included.

Adjunctive diagnostic value of MRI in the breast radial scar

PURPOSE

We sought to identify breast magnetic resonance imaging (MRI) criteria capable of influencing the differential diagnosis between radial scars related to benign proliferative disease and those associated with breast cancer with a view to proposing breast MRI as a promising and cost-effective modality to be carried out between mammography and surgical biopsy.

MATERIALS AND METHODS

From 1998 to June 2006, we studied 20 patients with a focal architectural distortion on mammography. All patients underwent contrast-enhanced breast MRI with a T1 Philips Gyroscan scanner and the acquisition of T1-weighted fast field echo, echo planar imaging (FFE EPI) axial dynamic sequences with a slice thickness of 3 mm. During postprocessing, subtracted images were assessed for morphological features, pattern of contrast enhancement, time-intensity curve and lesion enhancement rate.

RESULTS

Breast MRI depicted 27 lesions between 7 mm and 30 mm in size. Fifteen of the 27 breast lesions showed benign features, eight showed malignant features and four were classified as suspicious. Pathological examination confirmed the benignity of all 15 lesions showing benign MRI features and revealed the benign nature of the four lesions classified as suspicious.

CONCLUSIONS

Evaluation of breast MRI showed that enhancement rate and time-intensity curve were useful only in the differential diagnosis between benign and malignant breast lesions. Our experience confirmed that breast MRI has very high sensitivity and, in particular, a negative predictive value of 100%. Breast MRI could thus be considered a useful diagnostic tool that can guide the choice between follow-up or surgical excision of radial scars.

Radial scars/complex sclerosing lesions and malignancy in a screening programme: incidence and histological features revisited

AIMS

Radial scars (RS) are benign entities, frequently identified on screening mammography, which may be associated with malignancy. Much debate has been generated with regard to the optimum management of RS. We present our experience of RS in the first 5 years of a screening programme. The aim was to evaluate (i) the incidence of atypia and malignancy and (ii) the value of the preoperative core biopsy. We also further characterize the histological features.

METHODS AND RESULTS

One hundred and twenty-five histologically confirmed cases of RS were reviewed (111 had preoperative biopsies). Thirty-one (24.8%) patients had a final malignant diagnosis (11 with invasive malignancy) and 28 (22.4%) showed atypia (including lobular carcinoma in situ). In those with core biopsies and a final malignant diagnosis, 12 cases were categorized as B5 (41.3%), three as B4 (10.3%), 12 as B3 (41.3%) and two as B2 (7%). Common histological features included obliterated ducts and chronic inflammation with, less frequently, neural hyperplasia (16.8%) and perineural invasion (3.2%).

CONCLUSIONS

The high incidence of atypia and malignancy identified in our study justifies our policy of removing all mammographically detected RS. We emphasize the utility of preoperative core biopsy evaluation in permitting one-stage surgical therapy in those with B5 diagnoses.

Non-palpable ductal carcinoma in situ (DCIS) with microinvasion arising in a radial scar presenting with spiculation alone on mammograms: a case report

A case of ductal carcinoma in situ (DCIS) with microinvasion arising in a radial scar of the breast is presented. A 57-year-old woman visited our hospital with bloody discharge from her left nipple. There were no abnormal findings on cytology, carcinoembryonic antigen (CEA) level of nipple discharge was <500 ng/ml, and mammograms were normal. After 2 years of careful periodic follow-up, spiculation without a central core appeared on mammograms. The CEA level of the nipple discharge increased to 1,000 ng/ml. Ductgraphy showed a connection between the duct with the discharge and the center of the spiculation. Since these findings suggested malignancy, she underwent segmentectomy of the breast, and pathological examination showed a radial scar and DCIS with microinvasion in the ducts within the radiating bands of fibrous tissues. We discuss the characteristics of a radial scar and its relationship to breast cancer based on our experience and a review of the literature.

Interdependence of radial scar and proliferative disease with respect to invasive breast carcinoma risk in patients with benign breast biopsies

BACKGROUND

Radial scars (RS) are benign breast lesions that have been implicated as independent risk factors for invasive breast carcinoma (IBC).

METHODS

A retrospective cohort study of 9556 women who underwent biopsy between 1950-1986 and enrolled in the Nashville Breast Cohort was performed to investigate the association between RS in a benign breast biopsy and the risk of IBC. The risk associated with RS and coexistent proliferative disease (PD) was assessed adjusting for age at biopsy using a Cox hazards regression analysis with time-dependent covariates.

RESULTS

RS were identified in 880 women (9.2%). The average follow-up time was 20.4 years. Sixty-two women (7.0%) with RS developed IBC compared with 5.5% of controls. The relative risk of IBC associated with RS was 1.82 (95% confidence interval [95% CI], 1.2-2.7) at 10 years. Restricting the analysis to women age > 49 years increased the risk to 2.14 (95% CI, 0.6-2.8). These risks decreased with increasing years of follow-up. Approximately 92% of women with RS also had PD, but RS were present in only 1.3% of biopsies without PD. Analyses stratifying relative risk with regard to PD found RS to minimally elevate the relative risk of subsequent IBC.

CONCLUSIONS

RS in the absence of PD is uncommon. Although the presence of RS in a benign breast biopsy mildly elevates the risk of IBC risk, the current analysis indicated that this risk can be largely attributed to the category of coexistent PD. In women with both RS and atypical hyperplasia, recommendations for interventions beyond biopsy should be based on the extent of atypical hyperplasia.

Radial scar, complex sclerosing lesion and risk of breast cancer. Analysis of 175 cases in Northern Ireland

BACKGROUND

Controversy exists over the nomenclature and clinical significance of radial scar/complex sclerosing lesion (RS/CSL) of the breast. A retrospective analysis of cases diagnosed from 1988 to 2001 in Northern Ireland was performed to determine if any clinical difference exists between the diagnoses of radial scar and complex sclerosing lesion, and establish if lesions suggestive of RS/CSL require excision and/or follow-up.

PATIENTS

Patients with a diagnosis of RS/CSL from 1988 to 2001 were identified from the databases of the pathology laboratories serving specialist breast surgical units and the Northern Ireland Breast Screening Programme.

RESULTS

True RS/CSL was confirmed in 175 of 230 cases. There was no difference between RS and CSL regarding associated pathology in the specimen. 16.9% of cases identified at symptomatic clinics were associated with carcinoma in situ, and 15.7% with invasive breast carcinoma, compared to 4.7 and 2.3%, respectively in the screen detected group. One later carcinoma was found.

CONCLUSIONS

There is no clinical difference between the entities radial scar and complex sclerosing lesion. RS/CSL require excision due to their association with malignancy. In the absence of any independent risk factor for carcinoma no further follow-up of patients with RS/CSL is required.

Metaplastic spindle cell breast tumors arising within papillomas, complex sclerosing lesions, and nipple adenomas

Micropapillomas/papillomas and complex sclerosing lesions of the breast have been associated with a slightly increased risk for subsequent carcinoma, although benign squamous metaplasia and reactive hypercellular stroma are seen within these lesions. There are few reports of these fibrosclerotic lesions associated with metaplastic tumors. Here we describe a series of metaplastic tumors arising within fibrosclerotic breast lesions. Thirty-three metaplastic tumors associated with fibrosclerotic lesions were selected from a breast pathology consultative practice. Relevant clinical and pathological features were reviewed. Representative sections were evaluated immunohistochemically for expression of cytokeratins, vimentin, and smooth muscle and muscle-specific actins. Both the metaplastic component (spindled and squamous cells) and the glandular elements were graded. The metaplastic tumors arose within papillomas (20 cases), complex sclerosing lesions (7 cases), both papilloma and complex sclerosing lesions (3 cases), and nipple adenoma (3 cases). A majority of the metaplastic tumors showed a dominant spindle cell component with various degrees of atypia, ranging from fibromatosis-like (16 cases) to low-grade (13 cases), intermediate-grade (2 cases), and high-grade (2 cases) fibrosarcoma phenotype. Squamous metaplasia was present in 25 cases, and low-grade glandular elements, in 21 cases. Eleven tumors had a low-grade adenosquamous growth pattern. Ductal carcinoma in situ was present in 7 cases, and invasive mammary carcinoma, in 5 cases. The very low-grade tumors were histologically similar to limited areas of stromal reaction and myofibroblastic proliferation, seen in partially sclerotic micropapillomas/papillomas and complex sclerosing lesions, but usually more cellular. Cytokeratin positivity (13+/13 tested) supports the metaplastic nature of the more plump spindled cells. The spindle cells were also positive for vimentin (8+/8 tested) and smooth muscle (2+/5 tested) and muscle-specific actins (6+/6 tested). Spindle cell metaplastic tumors, from fibromatosis-like to fibrosarcoma, may arise within a variety of fibrosclerotic breast lesions.

Sclerosing lesions of the breast

Sclerosing lesions of the breast often mimic invasive carcinoma at the gross and microscopic levels and can pose a significant diagnostic challenge for surgical pathologists. This brief review is devoted to the histopathological characterization of 2 such sclerosing lesions of the breast: radial scars and sclerosing nipple adenomas. Microscopically, these lesions show similar morphological features: a zonal architectural pattern consisting of a central sclerotic region with entrapped distorted glands and a corona-like peripheral region with associated nonproliferative and proliferative fibrocystic changes. Important diagnostic features of these lesions are highlighted and contrasted with those of invasive carcinoma.

Pathology and clinical relevance of radial scars: a review

Radial scar (RS) is a benign, well recognised, radiological and pathological entity. Histologically, it is characterised by a fibroelastotic core with entrapped ducts and surrounding radiating ducts and lobules. Postmortem studies indicate that these lesions are present commonly in the population, especially in association with benign breast disease. In recent years, their clinical relevance has assumed more importance with the introduction of population based screening programmes. The exact pathogenesis of RS is unknown. Accumulating evidence indicates that they are associated with atypia and/or malignancy and, in addition, may be an independent risk factor for the development of carcinoma in either breast. In view of the association with atypia and malignancy, excision biopsy is justified in RS, although it has been argued that core biopsy evaluation and surveillance may be appropriate in selected patients.

Molecular and genetic abnormalities in radial scar

Hyperplasia of usual type (HUT) may be an early precursor of breast carcinoma and has been shown to contain molecular and genetic abnormalities previously seen in more advanced breast lesions, such as allelic imbalance (AI) and coexpression of estrogen receptor-alpha (ER) and the proliferation marker Ki67. We have examined hyperplastic and other areas from within radial scar (RS) for such abnormalities, to explore whether such regions of RS are similar at the molecular and genetic level to histologically similar lesions found independent of RS. Abnormal expression of ER and Ki67 in hyperplastic foci and other histologically distinct areas within RS was detected by dual-label immunofluorescence. Subtle differences in expression patterns were seen compared to similar lesions outside RS, with a lower overall level of ER overexpression in HUT within RS (P = 0.0012) and less evidence of the abnormal ER association with Ki67 (P = 0.004). AI of chromosome 16q and 8p was detected in RS, indicating that at least some areas of RS are clonal and neoplastic, but no clear relationship to ER dysregulation was found. Different genetic losses seen in microdissected areas of the same RS indicated clonal differences between these areas. The role of RS as a marker of malignancy and relative risk of breast cancer remains uncertain. Nonetheless, here we provide evidence that some molecular and genetic changes that occur to a greater degree in breast cancer and some premalignant breast lesions are present in a minority of RS.

Radial scars of the breast and breast carcinomas have similar alterations in expression of factors involved in vascular stroma formation

We recently reported that radial scars are an independent histologic risk factor for breast cancer. The reason for this association is not known. Given the importance of stromal-epithelial interactions in the pathogenesis of breast cancer, we studied radial scars for the expression of a number of factors known to be involved in the formation of vascular stroma in breast cancer. In situ hybridization was performed on formalin-fixed paraffin sections using (35)S-labeled riboprobes for collagen type 1, total fibronectin, extra domain A (ED-A)+ fibronectin, thrombospondin 1, vascular permeability factor (VPF)/vascular endothelial growth factor (VEGF), and one of its endothelial receptors, kinase insert domain-containing receptor (KDR) (vascular endothelial growth factor receptor [VEGFR-2]). Expression levels in radial scars (9 cases) were compared with those in normal breast tissue (15 cases) and infiltrating ductal breast carcinoma (4 cases). Factor VIII-related antigen immunostaining was used to define the distribution of microvessels in radial scars, carcinoma, and normal breast tissue. Compared with normal breast tissue, the radial scars showed focally increased numbers of blood vessels and focally increased expression of messenger RNA (mRNA) for collagen type 1, total fibronectin, ED-A+ fibronectin, thrombospondin 1, VPF/VEGF, and KDR. This pattern of mRNA overexpression was similar to that seen in the 4 invasive cancers. We conclude that there are similarities between radial scars and invasive breast cancers with regard to the level of mRNA expression for several factors involved in the formation of vascular stroma. These results suggest that a similar disturbance in stromal-epithelial interactions is present in both lesions.

Atypical ductal hyperplasia and ductal carcinoma in situ of the breast associated with perineural invasion

Perineural invasion is a histologic feature usually diagnostic of invasion in malignancies. In the breast, however, it has been associated with benign lesions such as sclerosing adenosis (SA), complex sclerosing lesion/radial scar (CSL/RS), and ductal carcinoma in situ (DCIS). This article describes perineural invasion associated with atypical ductal hyperplasia (ADH), florid hyperplasia without atypia (FH), and DCIS. All cases with a diagnosis of perineural invasion were selected from a series of 10,000 breast consult cases. Invasive mammary carcinomas were excluded. Fourteen cases of perineural invasion were found and associated with the following diagnoses: ADH (5), DCIS (3), FH (5), and ductal adenoma (1). Nine cases developed in CSL/RS, 4 cases in SA, and 1 case in a previous biopsy site of ductal adenoma; lesions were all less than 3 mm. The glands involving nerves showed cytologic and architectural features of the adjacent ADH, DCIS, and FH. Immunostaining for protein gene product (PGP) 9.5 marked nerves, and smooth muscle actin antibody highlighted the myoepithelial cells around glands. Perineural invasion seen in association with DCIS and ADH, in a background of CSL/RS and SA, may pose difficulty in diagnosis, especially in small biopsy specimens. It should be assessed with care to avoid misinterpretation as invasive mammary carcinoma.

Neoplastic and Malignant Lesions Involving or Arising in a Radial Scar: A Clinicopathologic Analysis of 17 Cases

Seventeen radial scars (RSs) containing or secondarily involved by lobular neoplasia (n = 8), ductal carcinoma in situ (DCIS) (n = 3), and invasive carcinoma (n = 6) are described. The patients ranged in age from 44 to 84 years with an average age of 58. Nine lesions presented as a palpable mass; three of the palpable masses were due to a variety of benign lesions associated with a radial scar. Eight radial scars were detected incidentally as a result of screening mammography; three of these cases manifested as stellate lesions. All lesions were unilateral. Microscopically, all radial scars had a stellate configuration, with a central fibroelastic core from which numerous ductules radiated. In eight cases, lobular neoplasia (LN) involved the peripheral ductules in a patchy fashion; seven of these cases were graded as LN 2 and one as LN 1. A grade II intraductal carcinoma with solid and cribriform patterns was noted in three cases, one of which was noteworthy because the central core contained DCIS (grade II) distorted by the dense fibroelastic tissue, mimicking an invasive pattern. An immunostain for actin demonstrated the presence of myoepithelial cells surrounding all the entrapped ductules confirming their noninvasive nature. An invasive carcinoma was present in the remaining six cases; these were predominantly focal and in the peripheral region of the radial scar. While all invasive carcinomas were well differentiated and ductal in type with abundant tubule formation, only one was a classic tubular carcinoma. In all six cases it was difficult to detect the malignant infiltrating nature of the lesion because of the associated stromal fibrosis and distortion of surrounding tubular structures. The occurence of neoplastic and malignant lesions involving or arising in a radial scar has received scant attention in the literature. This series indicates that the ducts and lobules emanating from radial scars can serve, albeit rarely, as the milieu for the development of or secondary involvement by lobular neoplasia, intraductal, or invasive carcinoma. It should be emphasized that these cases reflect a highly select group of problematic radial scars in a high-volume consultation practice; the vast majority of radial scars encountered in routine practice of surgical pathology are benign. At present there is no evidence that the scar element of the lesion serves as a precursor or promoter of the various neoplastic changes.

Metaplastic carcinoma of the breast arising within complex sclerosing lesion: a report of five cases

AIMS

This study presents a series of five cases in which metaplastic carcinoma, predominantly low-grade adenosquamous carcinoma, of the breast is seen arising within a background of a complex sclerosing lesion. This association has been recognized previously but has not been documented in detail. This study describes the characteristics of the components present in each case and discusses the existing literature. This observation adds further evidence to support an association between some types of invasive breast carcinoma and sclerosing lesions of the breast.

METHODS AND RESULTS

Four of these cases were received as referral cases for opinion. The fifth was received as part of the routine surgical workload within our own institution. Two patients presented following mammographic screening and three symptomatically; their mean age was 62 years (range 49-68). The mean lesion size was 16 mm (range 7-24). All five lesions showed features of a complex sclerosing lesion/radial scar in the form of central sclerosis with elastosis and radiating benign entrapped tubules. One had associated benign papillary structures and two had focal benign squamous metaplasia. Four cases showed coexisting but distinct areas of low-grade adenosquamous carcinoma with glandular and squamous epithelial differentiation in a spindle cell background. One case had associated undifferentiated spindle cell carcinoma. Detailed immunophenotypic characteristics of two cases are presented.

CONCLUSIONS

This series illustrates a postulated but previously unconfirmed association between an unusual form of metaplastic breast carcinoma (adenosquamous carcinoma) and complex sclerosing lesions. The mechanisms of induction of breast carcinoma are poorly understood but these observations further emphasize the potential for sclerosing lesion of the breast to be associated with, and possibly give rise to, invasive carcinoma of different types. The precise nature of the interaction between the pathological processes remains unclear.

Reactive spindle cell nodules of the breast after core biopsy or fine-needle aspiration

Reactive spindle cell nodules (RSCNs) arising postoperatively or after fine-needle aspiration (FNA) have been reported previously in the genitourinary tract and thyroid. We describe 18 cases of similar lesions in breast, associated with a history of core needle biopsy or FNA. The majority of the RSCNs (15 cases) were associated with papillary lesions or complex sclerosing lesions. The RSCNs were nonencapsulated and relatively nodular, measuring 1.5 to 9 mm. They were composed of spindle cells with mild to moderate nuclear pleomorphism and a low mitotic count. A network of small blood vessels, macrophages, and lymphocytes was present in all cases. Immunohistochemically, the spindle cells expressed smooth and specific muscle actins, supporting a myofibroblastic origin. The association of RSCNs with needle trauma to fibrosclerotic lesions, such as complex sclerosing lesions and papillary lesions that regularly have myofibroblasts, suggests an exuberant reparative cause. Recognition of this reactive process will avoid overdiagnosis of mammary spindle cell malignant neoplasm.

Radial scar and carcinoma of the breast: microscopic findings in 32 cases

We retrospectively reviewed the microscopic findings in 32 histologically confirmed radial scars in 31 women diagnosed in our unit during 1994-1998. The median age at diagnosis was 53 years (range 47-63 years). Thirty-one (97%) of 32 lesions presented as screen detected mammographic abnormalities (28 stellate lesions, 2 microcalcifications and only 1 architectural distortion). One lesion presented as a palpable breast mass. Stereotactic or ultrasound-guided fine needle aspiration cytology (FNAC) was performed in 28 cases. Cytological analysis of FNAs revealed malignant cells (C5) in 8 (29%) cases, highly suspicious cells (C4) in 3 (11%) cases, atypical benign cells (C3) in 7 (25%) cases and benign epithelial cells (C2) in 10 (35%) cases. All non-palpable lesions were surgically excised following wire localization. Histological examination of the breast specimens (mean weight=16 g) demonstrated, in addition to a radial scar, 6 invasive carcinomas (2 infiltrating ductal, 2 tubular, 1 mixed ductal/lobular and 1 secretory carcinoma) and 4 ductal carcinoma in situ lesions (2 high grade, 1 high grade with micro-invasion and 1 low grade) arising in the radial scar. Of the remaining cases the radial scar was associated with atypical epithelial hyperplasia in 2 cases and regular epithelial hyperplasia in 17 cases (4 florid and 13 mild to moderate). In the 10 cases associated with malignancy, 9 had FNAC and was reported as malignant (C5) in 6 (67%) cases, highly suspicious (C4) in 2 (22%) cases and atypical (C3) in 1 (11%). False positive FNAC (C5) occurred in two patients, one of whom presented with pleomorphic microcalcifications suggestive of ductal carcinoma in situ. This patient was treated with a wire guided segmental mastectomy. All invasive tumours were less than 20 mm in size (T1) and of these 4 were grade I and 2 were grade II. Axillary dissection was performed in 4 patients none of whom had axillary node metastases. Our study demonstrates a significant incidence of malignancy associated with radial scars (31%) suggesting that radial scars may be premalignant lesions. This is supported by detecting various stages of mammary carcinogenesis (atypical epithelial hyperplasia, ductal carcinoma in situ, and early invasive malignancy) in these lesions. Fine needle aspiration cytology seems to be unreliable in the diagnosis of radial scar associated malignancy (67% sensitivity and 91% specificity). Stellate lesions, therefore, should be excised to obtain an histological diagnosis regardless of cytological findings. Further studies examining the biology of radial scars are required.

Metaplastic breast tumors with a dominant fibromatosis-like phenotype have a high risk of local recurrence

BACKGROUND

In the current study the authors describe the clinicopathologic characteristics of a low grade variant of spindle cell metaplastic tumors of the breast. Previously these tumors have been considered within a larger group recognized as metaplastic carcinoma, including cases with higher grade features.

METHODS

Breast tumors comprised predominantly of low grade spindle cells, with sparse low grade epithelial elements, were selected. Clinical features as well as macroscopic, microscopic, and immunohistochemical findings were reviewed with emphasis on the biologic behavior and the differential diagnosis from other spindle cell lesions.

RESULTS

Of 30 tumors fulfilling strict criteria, 20 contained squamous or glandular elements associated with the spindle cells. Ten tumors were comprised entirely of low grade spindle cells with limited clustered epithelioid cells. At the periphery, all tumors showed a proliferation of bland spindle cells infiltrating the adjacent parenchyma and mimicking fibromatosis. The epithelioid cells and some spindle cells expressed both vimentin and one or more cytokeratins. Seven of eight patients treated by excisional biopsy developed local recurrence, whereas only one of ten patients treated with wide excisional biopsy developed a local recurrence. No distant or regional metastases occurred.

CONCLUSIONS

The presence of limited clusters of epithelioid cells along with a dominant fibromatosis-like pattern may be unique in the breast. The biologic potential of the fibromatosis-like, spindle cell, metaplastic breast tumors most likely is defined by their major histologic phenotype; they are capable of local recurrence with no demonstrated distant spread or regional metastases, as in pure fibromatosis of the breast.

Radial scars in benign breast-biopsy specimens and the risk of breast cancer

BACKGROUND

Radial scars are benign breast lesions of uncertain clinical significance. In particular, it is not known whether these lesions alter the risk of breast cancer in women with benign breast disease. We conducted a case-control study of women who had benign breast lesions with or without radial scars.

METHODS

We reviewed benign breast-biopsy specimens from 1396 women enrolled in the Nurses' Health Study, including 255 women in whom breast cancer subsequently developed and 1141 women without subsequent breast cancer (controls). The controls were matched to the women with subsequent breast cancer according to age and the year when the benign lesion was identified. The median follow-up after biopsy of the benign lesions was 12 years.

RESULTS

Radial scars were identified in biopsy specimens from 99 women (7.1 percent). Most biopsy specimens with radial scars had only one radial scar (60.6 percent), and they tended to be incidental microscopical findings (median size, 4.0 mm). The women with radial scars had a risk of breast cancer that was almost twice the risk of the women without scars, regardless of the histologic type of benign breast disease (relative risk, 1.8; 95 percent confidence interval, 1.1 to 2.9). Among women who had proliferative disease without atypia as compared with women who had nonproliferative disease, the relative risk of breast cancer was 3.0 (95 percent confidence interval, 1.7 to 5.5) for those with radial scars and 1.5 (95 percent confidence interval, 1.1 to 2.1) for those without radial scars. Among women with atypical hyperplasia as compared with women with nonproliferative disease, the relative risk of breast cancer was 5.8 (95 percent confidence interval, 2.7 to 12.7) for those with radial scars and 3.8 (95 percent confidence interval, 2.4 to 5.9) for those without radial scars.

CONCLUSIONS

Radial scars are an independent histologic risk factor for breast cancer.

Carcinoma and atypical hyperplasia in radial scars and complex sclerosing lesions: importance of lesion size and patient age

One hundred and twenty-six radial scars and complex sclerosing lesions from 91 women were examined to determine the incidence of and the clinical and pathological factors associated with the development of carcinoma and atypical hyperplasia within them. There was a clear relationship between the presence of carcinoma and atypical hyperplasia and the size of the lesion. This was not, however, a progressive relationship, there being a cut-off point about 6-7 mm, below which carcinoma was very uncommon and above which it was relatively frequent. A similar relationship was seen with patient age. Carcinoma was not seen in lesions removed from women under 40, was rare in the decade 41-50 and was relatively common above this age but with no further increase in the over 60s. A significantly higher incidence of carcinoma and atypical hyperplasia was encountered in scars detected by mammographic screening and could be explained by lesion size and the ages of the patients from which they were removed. No relationship was found between the presence of carcinoma within radial scars and complex sclerosing lesions and the existence of carcinoma in the residual breast tissue when direct extension was excluded. The carcinomas identified in the scars were of variable type and included small and large cell ductal carcinoma in situ, lobular carcinoma in situ and invasive carcinoma of tubular and ductal types. In situ carcinoma and atypical hyperplasia involved a very variable percentage of the epithelium of the lesions with mean values for ductal carcinoma in situ of 32%, lobular carcinoma in situ 25% and atypical hyperplasia 25%.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of common breast masses

Most breast lesions, including those that are malignant, are found by women themselves, which emphasizes the importance of breast self-examination. Comprehensive knowledge of breast anatomy and the characteristics that suggest that a mass is benign or suspicious aids primary care physicians in choosing the proper sequence of action. Drs Bland and Love discuss the common breast lesions and provide a detailed algorithm for management.

Anatomic markers of human premalignancy and risk of breast cancer

Epithelial hyperplasia of the breast carries an increased likelihood of carcinoma development, with most lesions best understood as markers of higher risk. The indication of increased cancer risk for more worrisome or complex histologic patterns has been supported in many studies. About 25% of women who underwent biopsies in the premammographic era had well-developed hyperplastic changes associated with an elevated risk of 1.5 to 2.0 times that of the general population when age and length of time of follow-up were considered. Somewhat fewer than 5% of women had specific patterns of atypical hyperplasia (AH) that approached the criteria of carcinoma in situ (CIS). These women with AH had a risk of cancer four to five times that of the general population, or about one half the risk associated with microscopic CIS. Only ductal CIS should be considered without question to be an intrinsic precancerous lesion because of its regular association with recurrence at the site of its initial diagnosis. Further studies indicated an appreciable interaction between AH and other nonanatomic risk factors, particularly a family history of breast cancer. Also, lower dosage estrogen replacement after menopause does not affect risk in any histologically defined group. The atypical hyperplastic lesions are more common in women undergoing biopsies on the indication of mammographic calcifications than because of palpable masses. The primary therapeutic implications of these premalignant lesions are intensified breast cancer surveillance and screening for these patients.

Prognostic parameters in breast cancer

Carcinoma of the breast is the most common cancer in Australian women. Current methods of treatment and refinements in therapeutic regimens are based on our understanding of the biological behaviour of the disease. Several prognostic parameters have been identified which predict survival and allow the selection of patients who may benefit from adjuvant therapies. The more important of these parameters include tumour size, histologic type, histologic grade, axillary lymph node status, estrogen receptor status and tumour growth fraction. Diagnostic pathologists who are responsible for the evaluation of these parameters should be cognizant of their relative prognostic values and also of other factors such as cellular antigens, lectin binding and oncogenes which may have potential roles in predicting survival and therapeutic responses. This review provides an update of prognostic parameters which are assessed through examination of the excised specimen.

Radial scars in women with breast cancer

In 84 consecutive autopsies of women with a clinical diagnosis of invasive breast cancer, radial scars were found in the contralateral breast in 35 cases (42%) by an extensive histopathologic method. Four women had radial scars on the ipsilateral side in the breast tissue available from the primary surgical procedure or at autopsy. One woman had an invasive breast cancer with morphologic features compatible with but not diagnostic of transition from a radial scar. Of the six radial scars with carcinoma in situ occurring in three women, three were of ductal and three of lobular type. In the remaining cases only radial scars with a benign appearance were found except for two with atypical hyperplasia. The frequency of radial scars was significantly higher in women with fibrocystic disease (55%) compared to women without (24%). Contralateral primary invasive and in situ breast cancer occurred in 68%. No difference in the frequency of radial scars in women with and without breast cancer was found and radial scars were not associated with any specific type of breast cancer. Our findings do not indicate a higher malignant potential of radial scars than of fibrocystic disease. It is suggested that only radial scars containing high-risk epithelial changes such as atypical hyperplasia and carcinoma in situ are associated with an increased risk of subsequent breast cancer development.

Patterns of basement membrane deposition in benign and malignant breast tumours

We have examined epithelial basement membranes in tissue samples of seven normal breasts, 64 benign breast lesions and 63 malignant breast tumours by immunocytochemistry, using polyclonal antisera specific for type IV collagen. In normal breast tissue as well as in all benign tumours a continuous basement membrane was found at the epithelial stromal interface. In benign proliferative lesions, epitheliosis and papillomatosis could be more accurately distinguished with basement membrane staining. This approach also facilitated the differentiation between sclerosing adenosis and tubular carcinoma, since the tubules in sclerosing adenosis are surrounded by a continuous basement membrane whereas in tubular carcinoma basement membranes are almost entirely absent. In radial scar lesions the tubules were always surrounded by intact basement membranes, which underlines the fact that these are benign lesions. In breast carcinoma we could not detect a relationship between histological grade and the extent of basement membrane deposition. However, in different tumour types the basement membrane alterations varied. In infiltrating lobular carcinoma of the alveolar type, fragments of basement membrane were found, whereas in the classic and trabecular type, basement membranes were absent, suggesting that the alveolar type may be an intermediate phase in the progression of lobular carcinoma in situ to infiltrating lobular carcinoma. It is concluded that basement membrane immunocytochemistry, using antibodies to type IV collagen, is useful in the differentiation between benign and malignant breast lesions and in the classification of breast neoplasms.

Myofibroblast activity of radial scars

Radial scars from 38 cases, comprising 12 associated with cancer and 26 with benign lesions, have been examined by electron microscopy. One-third of the lesions, regarded as being at an early stage of development, showed abundant spindle cells, which displayed the ultrastructural characteristics of myofibroblasts. These included many profiles of endoplasmic reticulum, prominent myofilaments and a close association with collagen and elastic fibres. The remaining 'mature' radial scars showed relatively few myofibroblasts, sparsely distributed in the stroma. The stromal cells associated with the 'early' lesions were seen in close proximity to degenerating parenchymal structures, which frequently showed loss of basal lamina. Obliteration of the central parenchymal component appeared to be a prominent feature of radial scar formation. The ultrastructural appearances are consistent with a progressive development of the lesion, associated with sporadic myofibroblast activity.