Treatment Strategy for Breast Benign Intraductal Papilloma: A Meta-Analysis.

Currently, the optimal treatment approach for breast benign intraductal papilloma (IDP) diagnosed via biopsy remains uncertain. There is ongoing debate regarding the feasibility of clinical follow-up and the criteria for selective surgical excision. This study aims to conduct a meta-analysis to determine the rate of upgrade from breast benign IDP and identify predictive factors associated with the conversion of benign IDP to high-risk lesions or carcinoma, which could guide healthcare practitioners in selecting the appropriate clinical treatment strategy. We conducted a comprehensive search across multiple databases (PubMed, Web Of Science, Cochrane Library, and Embase) for studies published between 2012 and 2023 that evaluated upgrade rates and predictive factors of breast benign IDP diagnosed via biopsy. In addition, we included studies that reported on the clinical follow-up of patients with breast benign IDP. In total, 32 studies comprising 7371 cases of biopsy-diagnosed breast benign IDP were included. Among these cases, 720 demonstrated an upgrade to high-risk lesions or carcinoma, resulting in an upgrade rate of 6.94% [95% confidence interval (CI): 3.0-8.0%]. A subgroup of 1713 patients was clinically followed up, demonstrating an average follow-up duration of 30.95 months. Among them, 26 cases experienced an upgrade to high-risk lesions or carcinoma, yielding an upgrade rate of 1.51% (95% CI 0.00-2.00). Furthermore, we identified nine predictive factors associated with the upgrading of breast benign IDP, which included age at diagnosis, personal history of breast cancer, family history of breast cancer, multiple IDPs, lesion size ≥ 10 mm, palpable mass, calcification, and the presence of mass and asymmetry in mammographic findings. Although the conversion rate of breast benign IDP to high-risk lesions or carcinoma is relatively low, timely identification of predictive factors associated with benign IDP upgrades may help selecting the optimal clinical treatment strategy, such as surgery for patients with benign IDP presenting one or more predictive factors, while clinical follow-up for those without specific risk factors.

Challenging diagnosis of male intraductal papilloma masquerading as eccrine hidradenoma in the breast: Case report.

RATIONALE: This article presents a challenging case involving an elderly male patient with a misdiagnosed intraductal mammary papilloma initially identified as a sweat adenoma through ultrasound imaging. The study aims to explore the histopathology, clinical presentations, and sonographic features of both conditions, emphasizing the contributing factors to the diagnostic misstep. PATIENT CONCERNS: A 61-year-old male reported a persistent left breast mass, along with pain and swelling, spanning a 6-month duration. DIAGNOSES: Ultrasound examination indicated a deep, square, mixed-echo mass in the left nipple, initially suggestive of a sweat adenoma. However, subsequent pathological analysis following resection under general anesthesia confirmed an intraductal papilloma. INTERVENTION: The patient underwent surgical resection of the left breast mass under general anesthesia. OUTCOME: Post-surgery, the patient exhibited satisfactory recovery; however, regrettably, he was lost to follow-up. LESSONS: This study underscores the challenge in differentiating between clear cell sweat adenoma and male intraductal mammary papilloma solely based on ultrasonic characteristics. It emphasizes the susceptibility of ultrasound-based diagnoses to misinterpretation, highlighting the critical need for a comprehensive pathological examination to establish a definitive diagnosis.

The Diagnostic Value of microRNA Expression Analysis in Detecting Intraductal Papillomas in Patients with Pathological Nipple Discharge.

Patients with pathological nipple discharge (PND) often undergo local surgical procedures because standard radiologic imaging fails to identify the underlying cause. MicroRNA (MiRNA) expression analysis of nipple fluid holds potential for distinguishing between breast diseases. This study aimed to compare miRNA expression levels between nipple fluids from patients with PND to identify possible relevant miRNAs that could differentiate between intraductal papillomas and no abnormalities in the breast tissue. Nipple fluid samples from patients with PND without radiological and pathological suspicion for malignancy who underwent a ductoscopy procedure were analyzed. We used univariate and multivariate regression analyses to identify nipple fluid miRNAs differing between pathologically confirmed papillomas and breast tissue without abnormalities. A total of 27 nipple fluid samples from patients with PND were included for miRNA expression analysis. Out of the 22 miRNAs examined, only miR-145-5p was significantly differentially expressed (upregulated) in nipple fluid from patients with an intraductal papilloma compared to patients showing no breast abnormalities (OR 4.76, p = 0.046), with a diagnostic accuracy of 92%. miR-145-5p expression in nipple fluid differs for intraductal papillomas and breast tissue without abnormalities and, therefore, has potential as a diagnostic marker to signal presence of papillomas in PND patients. However, further refinement and validation in clinical trials are necessary to establish its clinical applicability.

Bloody nipple discharge due to intraductal papilloma in an adolescent girl.

An early adolescent girl was referred to our breast surgery clinic with multiple right-sided breast masses and several months of unilateral bloody nipple discharge. MRI demonstrated multiple enhancing masses in the right breast with intrinsic hypertensive T1 signal of the ducts extending to the nipple. A biopsy showed partially sclerosed intraductal papillomas without atypia or malignancy. Following extensive counselling with the patient and her family, two palpable breast masses and a single central breast duct responsible for bloody nipple discharge were fully excised. Histopathological analysis showed unique overlapping features of resembling intraductal papilloma, nipple adenoma and fibroadenomas. The patient has had resolution of her bloody nipple discharge and excellent cosmetic outcomes post-surgery. Intraductal papilloma is rare in the adolescent population and the risk of concurrent and future malignancy is not well established. Thus, a tailored approach to the work-up and management of paediatric breast masses is essential.

Intraductal Papillomas.

The most common manifestation of papillary breast disease is intraductal papilloma (IDP). As breast disease management becomes more refined, increasing attention has been directed at determining which IDPs require excision, and which can be monitored. This article will discuss the most common factors currently impacting personalized decision-making.

The effect of delay of excisional biopsy on upstage rate for atypical ductal hyperplasia, flat epithelial atypia, intraductal papilloma, and radial scar.

PURPOSE: When Core Needle Biopsy (CNB) demonstrates Atypical Ductal Hyperplasia (ADH), Flat Epithelial Atypia (FEA), Intraductal Papilloma (IDP), or Radial Scar/Complex Sclerosing Lesion (RS), excisional biopsy (EB) is often performed to rule out underlying malignancy with upstage rates (UR) ranging between 1 and 20%. The COVID-19 pandemic led to delayed EB for many patients. We sought to evaluate whether this delay was associated with higher UR. METHODS: We performed a retrospective analysis of women who underwent CNB and then EB for ADH, FEA, IDP, or RS between 2017 and 2021 using an IRB-approved repository. UR was evaluated by days between CNB and EB. RESULTS: 473 patients met inclusion. 55 were upstaged to cancer (11.6%). 178 patients had pure ADH on CNB and 37 were upstaged (20.8%). 50 patients had pure FEA and 3 were upstaged (6%). 132 had pure IDP and 7 were upstaged (5.3%). 98 had pure RS and 1 was upstaged (1%). 7/15 (46.7%) had a combination of diagnoses or diagnosis with palpable mass and were upstaged. Days between CNB and EB were < 60 for 275 patients (58.1%), 60-90 for 108 (22.8%), 91-120 for 43 (9.1%), and > 120 for 47 (9.9%). There was no significant difference in UR (10.9% for < 60, 14.8% for 60-90, 7% for 90-120, and 12.8% for > 120, p = 0.54). UR for ADH was clinically increased after 60 days (27.8 vs. 17.5%), but this did not reach statistical significance (p = 0.1). CONCLUSION: Surgical delay was not associated with an increased UR.

Papillary lesions of the breast - review and practical issues.

Papillary lesions of the breast represent a heterogeneous group of neoplasm featuring fibrovascular cores covered by epithelial cells with or without intervening myoepithelial cells. According to the World Health Organization classification of breast tumors, papillary lesions of the breast are further classified into intraductal papilloma (including intraductal papilloma with atypical ductal hyperplasia /ductal carcinoma in situ), papillary ductal carcinoma in situ, encapsulated papillary carcinoma, solid papillary carcinoma (in situ and invasive) and invasive papillary carcinoma. The overlapping morphological features and immunohistochemical profiles make accurate diagnosis of breast papillary lesion a challenge for pathologists. In this review, the morphological and relevant immunohistochemical features of papillary lesions are discussed, with further emphasis on some commonly encountered practical diagnostic issues. A simple diagnostic algorithm will be established. The relevant molecular characteristics will be discussed as well.

Does previous history of cancer or atypia predict histologic upgrade for pure intraductal papillomas diagnosed via core biopsy? A study of 490 cases at a single institution.

BACKGROUND: Management of pure intraductal papillomas (IDP) without atypia diagnosed on core needle biopsy (CNB) remains controversial given highly variable rates of upgrade in the literature. AIM: We sought to identify clinical and histologic factors that predict upgrade to atypia or malignancy in a large population. METHODS AND RESULTS: A retrospective review was performed of all cases of pure IDP diagnosed on CNB and then surgically excised at a single institution from 2008 to 2018. Clinical, radiologic, and pathologic factors were compared in the no upgrade, upgrade to atypia, or upgrade to cancer groups. Univariate analysis was performed comparing no upgrade and upgrade to cancer or atypia. Four hundred and thirty nine patients were identified with a total of 490 IDP and a median age of 50 years (range 16-85). Of these patients, 54 (12.3%) were upgraded to atypia after surgical excision and five (1.1%) were upgraded to cancer. The presence of multiple papillomas in a single patient was a significant predictor of upgrade to cancer or atypia (p < .01), as well as age over ≥55 years (p < .01) and a prior history of cancer (p < .01). No other clinical, radiologic and histologic factors were found to be significant predictors of upgrade. 40/439 (9.1%) patients in the total cohort had prior history of cancer, and of these, 2/40 (5%) were found to have a new cancer after excision. CONCLUSIONS: In patients with pure IDP on CNB, the upgrade rate to malignancy was 1.1%, while 12.3% were upgraded to atypia. The clinical significance of identifying atypia in a papilloma is unknown, especially in a patient with a prior history of atypia or cancer. However, the majority of patients who were upgraded to either atypia or cancer had no prior history of high-risk or malignant breast disease and are therefore considered true clinical upgrades. As such excision for IDP should be considered.

Classical Lobular Carcinoma In Situ Arising From an Intraductal Papilloma of the Breast: A Case Report.

Intraductal papilloma of the breast is a benign, mass-forming, proliferative lesion with a papillary architecture confined within a duct. Lobular neoplasia can rarely arise from an intraductal papilloma of the breast. In this article, we report the morphologic features of a rare case of classical LCIS (lobular carcinoma in situ) arising from an intraductal papilloma in a 76-year-old woman. The monomorphic dyscohesive cells were present between the myoepithelial and luminal epithelial layer in the periphery of the papilloma. These cells partially obliterated the spaces between the papillae forming solid sheets. The monomorphic dyscohesive cells showed lack of E-cadherin expression and uniform staining for estrogen receptor. We review the histologic differential diagnosis and stress the importance of correct classification to ensure optimal care for patients. We also propose a new criterion for the distinction of lobular neoplasia within a papilloma.

Papillary neoplasms of the breast including upgrade rates and management of intraductal papilloma without atypia diagnosed at core needle biopsy.

Papillary neoplasms of the breast are a heterogeneous group of epithelial tumors nearly entirely composed of papillae. Their classification rests on the characteristics of the epithelium and the presence and distribution of the myoepithelial cells along the papillae and around the tumor. Papillary neoplasms of the breast can be diagnostically challenging, especially if only core needle biopsy (CNB) material is available. This review summarizes salient morphological and immunohistochemical features, clinical presentation, and differential diagnoses of papillary neoplasms of the breast. We include a contemporary appraisal of the upgrade rate to carcinoma (invasive carcinoma and ductal carcinoma in situ [DCIS]) and atypical hyperplasias in surgical excision specimens obtained following CNB diagnosis of papilloma without atypia, and a review of the available follow-up data in cases without immediate surgical excision.

Upgrade rate of intraductal papilloma diagnosed on core needle biopsy in a single institution.

The management of intraductal papilloma (IDP) diagnosed on core needle biopsy (CNB) is controversial due to the variable upgrade rates to breast carcinoma (BC) on subsequent surgical excision reported in the literature. The purpose of our study was to investigate the upgrade rate of IDP diagnosed on CNB to BC in subsequent surgical excision and the impact of clinical, pathologic, and radiologic variables. This is a retrospective cohort of all women who had a diagnosis of IDP on a CNB between 2005 and 2018 in a tertiary academic center with subsequent surgical excision. Upgrade was defined as ductal carcinoma in situ (DCIS) and invasive carcinoma on surgical excision. Statistical analyses included Pearson's chi-square, Wilcoxon rank-sum, and logistic regression. A total of 216 women with IDP in a CNB were included. Nineteen patients (8.8%) upgraded to BC in the overall cohort, including 14 DCIS and 5 invasive carcinomas. An upgrade rate of 27% was found in atypical IDP (14 of 51 cases), while only 3% of pure IDP upgraded to BC (5 of 165 cases). Older age (>53 years) at the time of biopsy (odds ratio [OR] = 1.05, 95% confidence interval [CI] = 1.01-1.09, p = 0.027) and concomitant atypical ductal hyperplasia (ADH) (OR = 9.69, 95% CI = 3.37-27.81, p < 0.0001) were significantly associated with upgrade. Our results support surgical excision of IDP on CNB when associated with ADH or diagnosed in women aged older than 53 years. The low surgical upgrade rate of 3% for pure IDP on CNB in younger women should be part of the management discussion.

Large breast lump with bloody nipple discharge: benign intraductal papilloma.

A 32-year-old woman presented with a 3 cm×3 cm left breast lump associated with bloody nipple discharge during her early pregnancy. Examination and ultrasonography showed benign features, whereas core needle biopsies revealed a benign papilloma. Six months after her delivery, a 6 cm×6 cm benign papilloma was completely excised via circumareolar incision. The majority of intraductal papillomas are small; however, they can also present as a large mass rarely. We should be wary of a malignant papillary lesion when there is the presence of atypia on core needle biopsy or imaging-histology discordance. A concordant benign papilloma with benign imaging findings is otherwise reassuring. Clinicians need to be aware of this uncommon presentation of large intraductal papilloma as a complete curative excision can be achieved through a cosmetically placed incision.

Immunohistochemical staining as supportive diagnostic tool for pseudomyxoma peritonei arising from intraductal papillary mucinous neoplasm: A report of two cases and literature review.

BACKGROUND/OBJECTIVES: Pseudomyxoma peritonei (PMP) arising from an intraductal papillary mucinous neoplasm of the pancreas (IPMN) is a rare condition. The diagnosis of IPMN as the origin of PMP is mainly inferred from the clinical course and the exclusion of PMP from other organs. The pathological diagnosis has not yet been established. To evaluate the usefulness of immunohistochemical staining for the diagnosis of the primary lesion of PMP as IPMN. METHODS: There are 2 cases of PMP arising from IPMN between March 2010 and December 2019 at National Center for Global Health and Medicine. A PubMed search that reported PMP arising from IPMN identified 16 additional cases. Diagnostic methods and clinicopathological features of 18 cases were compared. RESULTS: Four cases including our two cases used immunohistochemical staining for the diagnosis of PMP arising from IPMN. The correspondence of the immunohistochemical staining between PMP and IPMN was shown in the three cases including previously reported two cases and one of our two cases to identify the primary lesion of PMP as IPMN. In addition, we revealed that the comparison of the immunostaining pattern of PMP with the representative immunostaining pattern of the candidate primary lesions is helpful for the diagnosis of the primary lesion of PMP. CONCLUSIONS: Immunohistochemical staining is helpful to identify the primary lesion of PMP as IPMN.

Multiplex PCR analysis of apocrine lesions shows frequent PI3K-AKT pathway mutations in both benign and malignant apocrine breast tumors.

Pathological diagnosis of intraductal apocrine lesions can be challenging, because even benign apocrine lesions often show atypical cytology, and immunohistochemistry is of little assistance. A new diagnostic method for apocrine lesions is desirable. The mutations present in apocrine lesions have not been well studied. We performed a MassARRAY multiplex polymerase chain reaction (PCR) study of benign and malignant apocrine lesions, which included 152 mutations of 18 genes. We found that four of 11 benign lesions showed AKT1 or PIK3CA mutations, one of four noninvasive apocrine carcinomas showed a FBX4 mutation, two of 15 invasive apocrine carcinomas showed a PIK3CA mutation, and one invasive apocrine carcinoma showed both PIK3CA and TP53 mutations. The mutation frequency did not differ significantly between benign and malignant lesions (p = 0.683). We demonstrated that both benign and malignant apocrine lesions may contain mutations of genes in the PI3K-AKT pathway, this pathway could be a good therapeutic target of these diseases.

Histopathological evaluation of minor salivary gland papillary-cystic tumours: focus on genetic alterations in sialadenoma papilliferum and intraductal papillary mucinous neoplasm.

AIMS: Minor salivary gland tumours showing a predominant papillary-cystic structure are rare, and constitute a mixture of various types of neoplasm; thus, the histopathological assessment of these tumours poses a significant diagnostic challenge. We aimed to delineate the histological characteristics of these tumours and further mutational aspects with a particular focus on sialadenoma papilliferum (SP) and intraductal papillary mucinous neoplasm (IPMN). METHODS AND RESULTS: We retrieved 28 papillary-cystic tumours of the minor salivary glands, and performed histological re-evaluation and mutation analyses of several key oncogenes. The histological classifications were as follows: SP (n = 10), SP-like intraductal papillary tumour (SP-IPT) (n = 2), IPMN (n = 9), intraductal papilloma, cystadenoma, and cystadenocarcinoma (two, three and two respectively). Whereas SP typically consisted of a combination of exophytic squamous epithelium and endophytic intraductal papillary infoldings, SP-IPT lacked the exophytic component. SP and SP-IPT frequently harboured BRAF V600E mutations (75.0%), which were identified in both squamous and ductal components. IPMN was characterised by a well-demarcated cystic lesion filled exclusively with a papillary proliferation of mucinous cells and a high rate of AKT1 E17K mutations (88.9%). Intraductal papillomas were unilocular cystic lesions with intraluminal papillary growth of bland columnar cells. In contrast, both cystadenomas and cystadenocarcinomas showed a multicystic appearance with a papillary configuration. Cystadenocarcinomas invaded the surrounding tissue and were composed of markedly atypical tumour cells. CONCLUSION: The appropriate interpretation of histological findings and specific genetic alterations (e.g. BRAF V600E and AKT1 E17K in SP and IPMN) would be useful for the correct diagnosis of minor salivary gland papillary-cystic tumours.

Intraductal oncocytic papillary neoplasm of the pancreas: A systematic review.

BACKGROUND: Intraductal oncocytic papillary neoplasm of the pancreas (IOPN-P) is a rare subtype of intraductal papillary mucinous neoplasm (IPMN). This study was performed to summarize the clinicopathological features and management of IOPN-P. METHODS: English-language articles were searched from MEDLINE and EMBASE from the first report of IOPN-P in 1996 until 1 May 2019 following the methodology in the PRISMA guidelines. RESULTS: In total, 66 patients from 24 full articles were included in the final data analysis. The patients' average age was 61 years, and the male/female ratio was 1. Most lesions were large (average size, 5.50 cm), located in the pancreatic head, and found either incidentally or by uncharacteristic abdominal symptoms. IOPN-P was usually a cystic and solid lesion with or without mural nodules on radiological examination. A definitive diagnosis was often acquired from fine needle aspiration biopsy or postoperative pathology. All tumors were diagnosed as carcinoma in situ or minimally invasive carcinoma, necessitating surgical resection. The prognosis of IOPN-P was better than that of other IPMN subtypes, even when metastasis occurred. Recurrence after surgical resection of IOPN-P was rare. CONCLUSIONS: IOPN-P is rare among IPMN subtypes with unique pathological characteristics. Because of the nontypical symptoms and radiological findings, a definitive preoperative diagnosis usually depends on multimodal examinations. Management and surveillance of IOPN-P after surgical resection should be differentiated from those of other pancreatic benign cystic lesions because of its relative malignancy, but IOPN-P should also be differentiated from other IPMN subtypes and malignant cystic tumors because of its favorable prognosis.

Underestimation of breast cancer in intraductal papillomas treated with vacuum-assisted core needle biopsy.

OBJECTIVES: The aims of the study were as follows: 1) to determine the applicability of vacuum-assisted core needle biopsy in the diagnosis and management of intraductal papillomas of the breast; 2) to define factors which increase the risk for underestimation of breast cancer. MATERIAL AND METHODS: Between 2002-2017, a total of 222 cases of intraductal papillomas were diagnosed in one center (201 using vacuum-assisted core-needle ultrasound-guided biopsy and 21 using stereotactic biopsy). All patients under- went scheduled follow-up imaging. RESULTS: Pure papillomas were diagnosed in 158 women, whereas papillomas with atypia, in this case atypical ductal hyperplasia (ADH), were found in 29 subjects. In the latter group, 3 cases of invasive carcinoma and 5 cases of ductal carci- noma in situ (DCIS) were detected using open surgical biopsy. Breast cancer underestimation in that group of patients was 20%. Overall, ADH, whose presence increases the risk for BC by thirteen-fold as compared to other accompanying lesions, proved to be the most important predictive factor. Also, age, non-radical biopsy excision, and high BI-RADS ultrasound and mammogram scores increased the probability of malignancy. During the control follow-up, no cases of IP recurrence in the primary localization were observed in the group without open surgical biopsy. CONCLUSIONS: Vacuum-assisted core needle biopsy is an efficient tool in the diagnosis and management of intraductal papillomas of the breast. Surgical excision is not indicated in cases when a pure intraductal papilloma, and data correlation between the diagnosis and the clinical presentation were confirmed. Regardless, caution is advised if residual lesions were left and in older populations. Open surgical biopsy should remain the standard of care in cases with atypia and discordance between clinical and pathology data.

Intraductal papilloma of the breast - management.

In light of the growing availability of ultrasound testing and invasive diagnostic methods of the breast in everyday gyneco- logic practice, lesions of uncertain malignant potential, classified histologically as B3, have become a significant health issue. Intraductal papillomas (IPs) are the most common pathology in that group of lesions. Despite their benign histologic appearance, IPs may accompany malignant growths and the diagnosis made on the basis of biopsy material carries the risk of breast cancer (BC) underestimation. The article presents a review of the available literature on the management of patients diagnosed with intraductal papilloma at a standard core needle biopsy or vacuum-assisted core needle biopsy. The management is not uniform and depends not only on the verification technique or the accompanying pathological growths, but also on the result of clinical-pathological correlations. As it turns out, open surgical biopsy should not necessarily be recommended to every affected woman, and a growing number of sources have recently suggested that a control program would be sufficient in many cases. Thus, it is vital for gynecologists to be able to differentiate between those women who may be included in the annual ultrasound control program and those who require further surgical management.

[A Case Report of Breast Cancer Followed Up as Intraductal Papilloma].

The patient was a 50-year-old woman. She had been diagnosed with bilateral breast tumors at another hospital 5 years previously and was followed up every 2 months. Ultrasonography showed hypoechoic masses in her breasts. The largest tumor in the right breast was 15mm in diameter and located in region A, while that in the left breast was 8mm in diameter and located in region B. Magnetic resonance imaging(MRI)showed multiple bilateral breast tumors. The largest tumor was 12mm in diameter and was suggestive of breast cancer. Core needle biopsies(CNB)of the largest tumors in both breasts were performed. Intraductal papilloma(IDP)and low-grade intraductal papillary carcinoma were diagnosed in the right and left breasts, respectively, on immunohistochemical staining. We performed left nipple-sparing mastectomy with sentinel lymph node biopsy and right tumor excision for diagnoses of carcinoma of the left breast(cTisN0M0)and IDP of the right breast. The histopathological diagnosis of the left breast tumor was pT1aN0M0, triple negative breast cancer with extensive intraductal components, and that of the right breast tumor was IDP with atypical ductal hyperplasia. Chemotherapy was administered postoperatively. Several studies have reported that peripheral IDP often coexists with or follows the development of carcinoma. Therefore, we should also closely follow-upthe patient's right breast.

Are we overtreating intraductal papillomas?

BACKGROUND: The management of intraductal papillomas (IDPs) diagnosed on core needle biopsy (CNB) remains controversial regarding whether excision is required. We evaluated whether excision of IDPs might be overtreatment based on a consecutive patient population where all IDPs were routinely excised. MATERIALS AND METHODS: We retrospectively reviewed the records of consecutive patients treated with excision of IDPs at our institution from 2009 to 2016. We evaluated the rate of upgrade of IDPs on CNB and factors predicting for malignant upgrade. RESULTS: Of 153 CNB specimens, 136 (88.9%) were IDPs without atypia and 14 (9.2%) showed atypia. The overall upgrade rate on final pathology was 7.3% with 1.3% for invasive cancer, 2.7% for ductal carcinoma in situ, and 3.3% for atypical ductal hyperplasia. Of the 14 patients with atypia on CNB, two of these patients (14.2%) were found to have ductal carcinoma in situ. In the absence of atypia on CNB, upgrade rates were 1.5% for invasive and 1.5% for in situ carcinoma. Personal history of breast cancer and magnetic resonance imaging-guided biopsy predicted for malignant upgrade. CONCLUSIONS: IDPs on CNB have a low chance of harboring an occult malignancy. Given the low probability of upgrade to invasive breast cancer, it is reasonable to consider watchful surveillance in the absence of a prior personal history of breast cancer or atypia on CNB.