Precision HER2: a comprehensive AI system for accurate and consistent evaluation of HER2 expression in invasive breast Cancer.

BACKGROUND: With the development of novel anti-HER2 targeted drugs, such as ADCs, it has become increasingly important to accurately interpret HER2 expression in breast cancer. Previous studies have demonstrated high intra-observer and inter-observer variabilities in evaluating HER2 staining by human eyes. There exists a strong requirement to develop artificial intelligence (AI) systems to achieve high-precision HER2 expression scoring for better clinical therapy. METHODS: In the present study, we collected breast cancer tissue samples and stained consecutive sections with anti-Calponin and anti-HER2 antibodies. High-quality digital images were selected from immunohistochemical slides and interpreted as HER2 3+, 2+, 1+, and 0. AI models were trained and assessed using annotated training and testing sets. The AI model was trained to automatically identify ductal carcinoma in situ (DCIS) by Calponin staining and myoepithelial annotation and filter out DCIS components in HER2-stained slides using image-overlapping techniques. Furthermore, we organized two-phase validation studies. In phase one, pathologists interpreted 112 HER2 whole-slide images (WSIs) without AI assistance, whereas in phase two, pathologists read the same slides using the AI system after a washing period of 2 weeks. RESULTS: Our AI model greatly improved the accuracy of reading (0.902 vs. 0.710). The number of HER2 1 + patients misdiagnosed as HER2 0 was significantly reduced (32/279 vs. 65/279), and they benefitted from ADC drugs. In addition, the AI algorithm improved the intra-group consistency of HER2 readings by pathologists with different years of experience (intra-class correlation coefficient [ICC]: 0.872-0.926 vs. 0.818-0.908), with the improvement most pronounced among junior pathologists (0.885 vs. 0.818). CONCLUSIONS: We proposed a high-precision AI system to identify and filter out DCIS components and automatically evaluate HER2 expression in invasive breast cancer.

Extramammary breast cancer of the vulva.

A woman in her 70s was seen in the gynaecology outpatient clinic with a swelling on the right side of the vulva. Surgical excision of the lesion revealed unexpectedly an extensive ductal carcinoma in situ with a focus of a grade 2 invasive ductal carcinoma arising in extramammary breast tissue of the vulva. Postoperative staging studies showed normal breasts, with no evidence of disease elsewhere. The patient underwent a wider excision of the right vulva and sentinel node biopsy of the right inguinal region, which revealed no further disease. The patient is currently taking adjuvant hormonal therapy and has remained disease free at 2-year follow-up. This case underscores the importance of considering rare presentations of vulvar malignancies and the necessity for a multidisciplinary approach in managing such cases.

Trajectory of Subsequent Breast Cancer Diagnoses in a Diverse Patient Cohort with Breast Atypia.

BACKGROUND: Proliferative breast atypical lesions, including atypical ductal hyperplasia (ADH) and lobular intraepithelial neoplasms (LIN), represent benign entities that confer an elevated risk of ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC). However, the timing of disease progression is variable and risk factors associated with the trajectory of disease are unknown. METHODS: Patients diagnosed with ADH or LIN from 1992 to 2017 at an academic center were identified. Early progression was defined as DCIS or IBC diagnosed within 5 years following the initial atypia diagnosis. Unadjusted cancer-free survival was estimated using the Kaplan-Meier method. Demographics, clinicopathologic features, and use of chemoprevention were compared between the early and late development groups. RESULTS: Overall, 418 patients were included-73.7% with ADH and 26.3% with LIN. Over a median follow up of 92.1 months, 71/418 (17.0%) patients developed IBC (57.7%) or DCIS (42.3%). Almost half (47.9%, 34/71) were diagnosed within 5 years of their initial atypia diagnosis, and 52.1% (37/71) were diagnosed after 5 years. Patient and atypia characteristics were not associated with rate of events or time to events. There was a trend of early events being more often ipsilateral (76.5% early vs. 54.1% late; p = 0.13) versus contralateral. CONCLUSIONS: In a large cohort of patients with breast atypia and long-term follow up, 17% experienced subsequent breast events, with approximately half of the events occurring within the first 5 years following the initial atypia diagnosis. Clinical features were not associated with the trajectory to subsequent events, supporting that atypia signals both local and overall malignancy risk.

Participation in a High-Risk Program Is Associated with a Diagnosis of Earlier-Stage Disease Among Women at Increased Risk for Breast Cancer Development.

BACKGROUND: High-risk programs provide recommendations for surveillance/risk reduction for women at elevated risk for breast cancer development. This study evaluated the impact of high-risk surveillance program participation on clinicopathologic breast cancer features at the time of diagnosis. METHODS: Women followed in the authors' high-risk program (high-risk cohort [HRC]) with a diagnosis of breast cancer from January 2015 to June 2021 were identified and compared with the general population of women undergoing breast cancer surgery at Memorial Sloan Kettering Cancer Center (MSK; general cohort [GC]) during the same period. Patient and tumor factors were collected. Clinicopathologic features were compared between the two cohorts and in a subset of women with a family history of known BRCA mutation. RESULTS: The study compared 255 women in the HRC with 9342 women in the GC. The HRC patients were slightly older and more likely to be white and have family history than the GC patients. The HRC patients also were more likely to present with DCIS (41 % vs 23 %; p < 0.001), to have smaller invasive tumors (pT1: 100 % vs 77 %; p < 0.001), and to be pN0 (95 % vs 81 %; p < 0.001). The HRC patients had more invasive triple-negative tumors (p = 0.01) and underwent less axillary surgery (p < 0.001), systemic therapy (p < 0.001), and radiotherapy (p = 0.002). Among those with a known BRCA mutation, significantly more women in the HRC underwent screening mammography (75 % vs 40 %; p < 0.001) or magnetic resonance imaging (MRI: 82 % vs 9.9 %; p < 0.001) in the 12 months before diagnosis. CONCLUSIONS: Women followed in a high-risk screening program have disease diagnosed at an earlier stage and therefore require less-intensive breast cancer treatment than women presenting to a cancer center at the time of diagnosis. Identification of high-risk women and implementation of increased surveillance protocols are vital to improving outcomes.

Multicentric reticulohistiocytosis revealing a ductal breast cancer in situ: A case report with dermoscopic and histopathological findings. / Reticulohistiocitosis multicéntrica reveladora de cáncer de mama ductal in situ: reporte de caso con aspectos dermatoscópicos e histopatológicos.

Multicentric reticulohistiocytosis is a rare non-Langerhans cell histiocytosis of unknown etiology. It is classified as multicentric because of multisystem involvement. The disease predominantly affects the skin and joints, but visceral involvement is possible. Multiple erythematous-brownish, pruritic nodules and papules on the face, hands, neck, and trunk are characteristic. It is associated with autoimmune diseases, or malignant neoplasms are seen in 20% to 30% of patients with multicentric reticulohistiocytosis. The diagnosis is based on histopathology of affected tissues. As it is an underreported disease, there is no standardized treatment. A case of multicentric reticulohistiocytosis is reported as a paraneoplastic manifestation of ductal breast cancer, being successfully treated with no recurrence after two years of follow-up. Few cases of multicentric reticulohistiocytosis associated with breast cancer have been reported in the literature.

La reticulohistiocitosis multicéntrica es una enfermedad inflamatoria, una histiocitosis de células no Langerhans, poco frecuente y de etiología desconocida. Se clasifica como multicéntrica al presentar compromiso multisistémico. La enfermedad afecta predominantemente a la piel y las articulaciones, pero es posible la afectación visceral. Las manifestaciones cutáneas se caracterizan por múltiples nódulos y pápulas de color eritemato-marronáceas, pruriginosas en la cara, manos, cuello y tronco. Se asocia a enfermedades autoinmunes y neoplasias malignas, observándose entre el 20 y el 30% de los pacientes con reticulohistiocitosis multicéntrica. Su diagnóstico se realiza sobre la base de la histopatología de tejidos afectados. Al ser una enfermedad poco reportada, no existe tratamiento estandarizado. Se reporta un caso de reticulohistiocitosis multicéntrica como manifestación paraneoplásica a un cáncer ductal de mama, siendo tratadas con éxito, sin recidivas luego de dos años de seguimiento. Pocos casos se han reportado en la literatura de reticulohistiocitosis multicéntrica asociado a cáncer mamario.

Radial sclerosing lesions found on core needle biopsy: excision can be safely avoided.

AIMS: 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. METHODS AND 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.

B3 Breast Lesions: Positive Predictive Value and Follow-Up on a Large Single-Institution Series.

INTRODUCTION: Lesions of uncertain malignant potential (B3) represent 10% of core needle biopsies (CNBs) or vacuum-assisted breast biopsies (VABBs). Traditionally, B3 lesions are operated on. This study investigated the association between B3 subtypes and malignancy to determine the best management. METHODS: Pre- and postoperative histological reports from 226 patients, who had undergone excisional surgery for B3 lesions, following CNB or VABB, were retrospectively analyzed. The correlation between the CNB/VABB diagnosis and the final pathology was investigated, along with the correlation between malignancy upgrade and the type of mammographic lesion. The positive predictive value (PPV) of malignancy of B3 lesions was calculated by simple logistic regression. Patients without cancer diagnosis underwent a 7-y follow-up. RESULTS: Pathology showed 171 (75.6%) benign and 55 (24.3%) malignant lesions. The PPV was 24.3% (P = 0.043), including 31 (13.7%) ductal carcinomas in situ and 24 (10.6%) invasive carcinomas. The most frequently upgraded lesions were atypical ductal hyperplasia, 34.2% (P = 0.004), followed by lobular intraepithelial neoplasia, 27.5% (P = 0.025). The median diameter of mammographic lesions was 1.5 [0.9-2.5] cm, while for surgical specimens, it was 5 [4-7] cm (P < 0.0001). Mammographic findings and histology showed a significant correlation (P = 0.038). After a 7-y follow-up, 15 (8.9%) patients developed carcinoma, and 7 patients (4%) developed a new B3 lesion. CONCLUSIONS: We can conclude that atypical ductal hyperplasia and lobular intraepithelial neoplasia still require surgery for a significant PPV. Other types that lacked significance or confidence intervals were too wide to draw any conclusion.

Deep learning of mammogram images to reduce unnecessary breast biopsies: a preliminary study.

BACKGROUND: Patients with a Breast Imaging Reporting and Data System (BI-RADS) 4 mammogram are currently recommended for biopsy. However, 70-80% of the biopsies are negative/benign. In this study, we developed a deep learning classification algorithm on mammogram images to classify BI-RADS 4 suspicious lesions aiming to reduce unnecessary breast biopsies. MATERIALS AND METHODS: This retrospective study included 847 patients with a BI-RADS 4 breast lesion that underwent biopsy at a single institution and included 200 invasive breast cancers, 200 ductal carcinoma in-situ (DCIS), 198 pure atypias, 194 benign, and 55 atypias upstaged to malignancy after excisional biopsy. We employed convolutional neural networks to perform 4 binary classification tasks: (I) benign vs. all atypia + invasive + DCIS, aiming to identify the benign cases for whom biopsy may be avoided; (II) benign + pure atypia vs. atypia-upstaged + invasive + DCIS, aiming to reduce excision of atypia that is not upgraded to cancer at surgery; (III) benign vs. each of the other 3 classes individually (atypia, DCIS, invasive), aiming for a precise diagnosis; and (IV) pure atypia vs. atypia-upstaged, aiming to reduce unnecessary excisional biopsies on atypia patients. RESULTS: A 95% sensitivity for the "higher stage disease" class was ensured for all tasks. The specificity value was 33% in Task I, and 25% in Task II, respectively. In Task III, the respective specificity value was 30% (vs. atypia), 30% (vs. DCIS), and 46% (vs. invasive tumor). In Task IV, the specificity was 35%. The AUC values for the 4 tasks were 0.72, 0.67, 0.70/0.73/0.72, and 0.67, respectively. CONCLUSION: Deep learning of digital mammograms containing BI-RADS 4 findings can identify lesions that may not need breast biopsy, leading to potential reduction of unnecessary procedures and the attendant costs and stress.

Adenocarcinoma of anogenital mammary gland type arising from encapsulated papillary carcinoma: A rare vulvar tumor mimicking breast carcinoma.

Anogenital mammary-like glands are normal structures of the anogenital region. Tumors originating from these glands often exhibit a striking resemblance to their mammary gland counterparts. Herein, we present a rare case of adenocarcinoma of mammary gland type in the vulva of a 69-year-old female. Histopathologic examination revealed a complex lesion, which included a large encapsulated papillary carcinoma (EPC) with associated invasive carcinoma of mammary gland type and ductal carcinoma in situ (DCIS). The invasive component consisted mostly of invasive ductal carcinoma of no special type, with a notable focus of invasive mucinous carcinoma. p40 immunostain demonstrated a lack of myoepithelial cells in both the EPC and invasive carcinoma, but such cells expressed p40 around the ducts involved by DCIS. The main component of this lesion, EPC, was characterized by a papillary proliferation within a cystic space surrounded by a fibrous capsule without a myoepithelial layer. The histopathologic features of anogenital EPC closely resemble cutaneous hidradenoma papilliferum. Indeed, there have been a few reports in the literature describing cases where in situ and invasive carcinoma arose from a preexisting hidradenoma papilliferum. As tumors of anogenital mammary-like glands bear a closer resemblance to breast lesions than to skin tumors, we recommend that they be aligned with the classification of well-established breast lesions rather than cutaneous adnexal tumors.

Non-mass-type ductal carcinoma in situ of the breast on ultrasound: Features and pathological analysis.

AIMS: The aims of this study were to investigate the ultrasound features of non-mass-type ductal carcinoma in situ (DCIS) of the breast and conduct a pathological analysis. MATERIAL AND METHODS: Ultrasound images of 32 cases of non-mass-type DCIS of the breast, collected between September 2014 and June 2016, were analyzed. The characteristics of the lesions, including border, internal echogenicity, local glandular hyperplasia, micro-calcification, and intra-tumoral blood flow resistance index (RI), were analyzed, and a concurrent pathological analysis was conducted. RESULTS: Obvious local glandular hyperplasia was commonly observed in the 32 cases of non-mass-type DCIS of the breast. The internal echogenicity varied in intensity, exhibiting a "leopard pattern" or "zebra pattern." Color Doppler imaging revealed abundant blood flow signals within the lesion with an RI of >0.7. Isolated duct dilatation and micro-calcifications were occasionally observed within the lesions. High-grade DCIS was the predominant pathological type of non-mass-type DCIS. CONCLUSIONS: Non-mass-type DCIS of the breast often presents with obvious local glandular hyperplasia and varying internal echogenicity. High-grade DCIS is the frequent pathological type. Color Doppler imaging and RI measurement can assist in diagnosing non-mass-type DCIS of the breast.

Surgical outcomes of total duct excision in the diagnosis and management of nipple discharge.

INTRODUCTION: Total duct excision (TDE) is performed for the diagnosis and management of nipple discharge. The Association of Breast Surgery's recent guidelines recommend considering diagnostic surgery for single-duct, blood-stained or clear nipple discharge, and for symptomatic management. METHODS: We retrospectively reviewed the diagnostic and surgical outcomes of all cases of TDE between January 2013 and November 2019. RESULTS: In total, 259 TDEs were carried out: 219 for nipple discharge, 29 for recurrent mastitis, 3 for screening abnormalities and 8 for breast lumps. Of the nipple discharge group, 121 had blood-stained discharge. Mean patient age was 52 years (range 19-81). Median follow-up time was 45 months (interquartile range 24-63). The following cases were identified on histopathology: 236 benign breast changes, 10 atypical ductal hyperplasia, 4 lobular carcinoma in situ, 2 low-grade ductal carcinoma in situ (DCIS), 3 intermediate-grade DCIS, 2 high-grade DCIS and 2 invasive ductal carcinomas. In total, 3.5% of patients who underwent TDE had a diagnosis of DCIS or invasive carcinoma. Blood-stained discharge was associated with a significant increase in risk of DCIS or carcinoma compared with other nipple discharge colours (p = 0.043). The most common complications of TDE were infection, poor wound healing and haematoma. Nipple discharge recurred in 14.2% of cases. CONCLUSIONS: TDE can be considered for the diagnostics and management of nipple discharge. Blood-stained nipple discharge increases the risk of DCIS or malignancy, but the majority of the time TDE reveals benign breast pathology.

Feasibility of Omitting Sentinel Lymph Node Biopsy in an Under-screened Cohort of Breast Cancer Patients With a Premastectomy Diagnosis of Ductal Carcinoma In Situ.

BACKGROUND: Nodal involvement in ductal carcinoma in situ (DCIS) is rare. In patients with DCIS diagnosis prior to mastectomy, a sentinel lymph node biopsy (SLNB) is usually performed during mastectomy, to avoid the risk of reoperation and the non-identification of SLN subsequently, should there be an upgrade to invasive cancer. We aimed to study the feasibility of omitting SLNB in an under-screened cohort, with mostly symptomatic patients and DCIS diagnosis before mastectomy, by determining the upgrade rate to invasive cancer/ DCIS microinvasion (DCISM) and its associated risk factors. METHODS: Patients with pure DCIS diagnosis premastectomy were reviewed retrospectively. Patients with known DCISM or invasive cancer before mastectomy and bilateral cancers were excluded. Patients' demographics, radiological and pathological data premastectomy were analyzed. RESULTS: A total of 189 patients were included. The mean age was 53.8 (range: 29-85) years old. About 64.4% presented with symptoms. 36.0% and 15.3% upgraded to invasive cancer and DCISM on mastectomy respectively. Palpable tumor (P = .0036), large size on ultrasound (P = .0283), tumor seen on mammogram and ultrasound (P = .0082), ultrasound-guided biopsy (P < .0001), high-grade DCIS on biopsy (P = .0350) and no open biopsy/lumpectomy before mastectomy (P < .0001) were associated with the upgrade, with the latter factor remaining significant after multivariable analysis. Nodal involvement was 8.47% and was associated with invasive cancer (P < .0001). CONCLUSION: In a cohort who had DCIS diagnosis before mastectomy and were mostly symptomatic, the upgrade rate was 51.3%. Despite the high upgrade rate, nodal involvement remained comparable. Risk factors could select patients for omission of upfront SLNB, with a delayed SLNB planned if needed.

Atypia Involving Fibroadenomas: Outcomes and Upgrade Rates.

OBJECTIVE: Fibroadenomas (FAs) involved by atypia are rare. Consensus guidelines for management of FAs involved by atypia when diagnosed on image-guided biopsy do not exist because of limited data reporting surgical upgrade rates to ductal carcinoma in situ (DCIS) or invasive malignancy. Therefore, these lesions commonly undergo surgical excision. METHODS: This single-institution retrospective study identified cases of FAs involved by atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and/or lobular carcinoma in situ (LCIS) diagnosed on image-guided biopsy between January 2014 and April 2023 to determine upgrade rates. Cases with incidental atypia adjacent to but not involving FAs were excluded. RESULTS: Among 1736 FAs diagnosed on image-guided biopsy, 32 cases (1.8%) were FAs involved by atypia including 43.8% (14/32) ALH, 28.1% (9/32) ADH, 18.8% (6/32) LCIS, 6.3% (2/32) LCIS + ALH, and 3.1% (1/32) unspecified atypia. The most common imaging finding was a mass. Most cases, 81.3% (26/32), underwent subsequent surgical excisional biopsy. A single case of ADH involving and adjacent to an FA was upgraded to FA involved by low-grade DCIS on excision for an overall surgical upgrade rate of 3.8%. There were no cases upgraded to invasive malignancy. For those omitting surgical excision, there was no subsequent malignancy diagnosis at the FA biopsy site over a mean follow-up of 73 months. CONCLUSION: Cases of radiologic-pathologic concordant FAs involved by atypia have a low upgrade rate of 3.8% and should undergo multidisciplinary review. Larger multi-institutional analysis is needed to determine whether guidelines for excision of atypia should apply to atypia involving FAs.

Using the DNA Integrity Number to Analyze DNA Quality in Specimens Collected from Liquid-Based Cytology after Fine-Needle Aspiration of Breast Tumors and Lesions.

INTRODUCTION: Cancer genome analysis using next-generation sequencing requires adequate and high-quality DNA samples. Genomic analyses were conventionally performed using formalin-fixed paraffin-embedded sections rather than cytology samples such as cell block or smear specimens. Specimens collected from liquid-based cytology (LBC) have the potential to be sources of high-quality DNA suitable for genetic analysis even after long-term storage. METHODS: We collected breast tumor/lesion fractions from 92 residual LBC specimens using fine-needle aspiration (FNA) biopsy, including breast carcinoma (1 invasive carcinoma and 4 ductal carcinomas in situ), papillomatous lesion (5 intraductal papillomas), and fibroepithelial lesion (19 phyllodes tumors and 53 fibroadenomas) samples, and others (1 ductal adenoma, 1 hamartoma, 1 fibrocystic disease, and 7 unknown). DNA was extracted from all samples and subjected to DNA integrity number (DIN) score analysis. RESULTS: Average DIN score collected from 92 LBC specimens was significantly higher score. In addition, high-quality DNA with high DIN values (7.39 ± 0.80) was successfully extracted more than 12 months after storage of residual LBC specimens. CONCLUSION: Residual LBC specimens collected from FNA of the breast were verified to carry high-quality DNA and could serve as an alternate source for genetic analysis.

Male ductal carcinoma in situ: diagnosis and management of a rare disease in men.

Ductal carcinoma in situ is very rare in male patients, accounting for approximately 5%-7% of all male breast cancers. We present a case of a man in his early 70s who presented with bloody nipple discharge and gynaecomastia and was subsequently diagnosed with ductal carcinoma in situ (DCIS). We discuss his management with surgical resection and the consideration of adjuvant treatment. We also review the existing literature on the presentation, diagnosis and management of DCIS in men.

Management and risk of upgrade of atypical ductal hyperplasia in the breast: A population-based retrospective cohort study.

BACKGROUND: International guidelines recommend open surgery for atypical ductal hyperplasia (ADH) in the breast due to risk of underestimating malignant disease. Considering the ongoing randomized trials of active surveillance of low-risk ductal carcinoma in situ (DCIS), it seems reasonable to define a low-risk group of women with ADH where a conservative approach is appropriate. The aim here was to evaluate the management and risk for upgrade of lesions diagnosed as ADH in percutaneous breast biopsies in two Swedish hospitals. METHODS: All women with a screen-detected or symptomatic breast lesion breast imaging-reporting and data system (BI-RADS) 2-4 and a percutaneous biopsy showing ADH between 2013 and 2022 at Sundsvall Hospital and Umeå University Hospital were included. Information regarding imaging, histopathology, clinical features, and management was retrieved from medical records. Odds ratio (OR) and 95% confidence intervals (CI) for upgrade to malignant diagnosis after surgery were calculated by logistic regression analysis. RESULTS: Altogether, 101 women were included with a mean age 56.1 (range 36-93) years. Most women were selected from the national mammography screening program due to microcalcifications. Biopsies were performed with vacuum-assisted biopsy (60.4%) or core-needle biopsy (39.6%). Forty-eight women (47.5%) underwent surgery, of which 11 were upgraded to DCIS, and 7 to invasive breast cancer (upgrade rate 37.5%). Among the 53 women managed conservatively (median follow-up 74 months), one woman (1.9%) developed subsequent ipsilateral DCIS. The combined upgrade rate was 18.8%. No clinical variable statistically significantly correlating to risk of upgrade was identified. CONCLUSIONS: The upgrade rate of 37.5% in women undergoing surgery compared to an estimated 5-year risk of ipsilateral malignancy at 1.9% in women managed conservatively indicate that non-surgical management of select women with ADH is feasible. Research should focus on defining reproducible criteria differentiating high-risk from low-risk ADH.

Benign Adenomyoepithelioma: An Unrecognised Precursor of Ductal Carcinoma in Situ in Patient With Lynch Syndrome.

Currently, there is no robust evidence demonstrating a clear association between Lynch syndrome and non-malignant breast pathology such as adenomyoepithelioma. We report a case of benign breast adenomyoepithelioma, which after recurrence was associated with ductal carcinoma in-situ (DCIS) in a 41-year-old woman with Lynch syndrome, who lacked significant family history of breast or ovarian cancer. Both, the adenomyoepithelioma and DCIS were found to have nuclear loss of MSH2/MSH6 by immunohistochemistry, while germline testing confirmed MSH2 gene mutation. Concordant loss of MSH2 in both lesions in the context of a MSH2 pathogenic variant in this patient with Lynch syndrome illustrates that the benign adenomyoepithelioma behaved as a likely precursor of DCIS. Our report provides a novel perspective that in some patients with Lynch syndrome adenomyoepithelioma may represent a pre-malignant precursor lesion of DCIS.

Update on Management of Ductal Carcinoma in Situ.

Ductal carcinoma in situ (DCIS) represents 18% to 25% of all diagnosed breast cancers, and is a noninvasive, nonobligate precursor lesion to invasive cancer. The diagnosis of DCIS represents a wide range of disease, including lesions with both low and high risk of progression to invasive cancer and recurrence. Over the past decade, research on the topic of DCIS has focused on the possibility of tailoring treatment for patients according to their risk for progression and recurrence, which is based on clinicopathologic, biomolecular and genetic factors. These efforts are ongoing, with recently completed and continuing clinical trials spanning the continuum of cancer care. We conducted a review to identify recent advances on the topic of diagnosis, risk stratification and management of DCIS. While novel imaging techniques have increased the rate of DCIS diagnosis, questions persist regarding the optimal management of lesions that would not be identified with conventional methods. Additionally, among trials investigating the potential for omission of surgery and use of active surveillance, 2 trials have completed accrual and 2 clinical trials are continuing to enroll patients. Identification of novel genetic patterns is expanding our potential for risk stratification and aiding our ability to de-escalate radiation and systemic therapies for DCIS. These advances provide hope for tailoring of DCIS treatment in the near future.