Management of pediatric and adolescent breast masses

Clinicopathological pattern of breast lesions in children and adolescents

Background

Breast lesions are not common in children and adolescents. The aim of this study is to retrospectively survey the clinicopathological pattern of breast lesions in children and adolescents in our setting.

Materials and method

This is a retrospective study of all breast specimens from children and adolescents that were histopathologically diagnosed in University of Uyo Teaching Hospital.

Results

The youngest patients seen were 11 years old, with mean age of 17.1 ± 1.91. The commonest clinical diagnoses were fibroadenoma (n=134, 72.4%). Thirty-five-point seven percent of the patients presented within 6 months of noticing the lump. The mean size of the lumps was 6.2cm ± 3.9. Fibroadenoma was the most common benign diagnosis and the most common histopathologic diagnosis in this study. The mean age of patients with fibroadenoma was 17.15±1.83.

Conclusion

The pattern of breast lesions in adolescents in Uyo is similar to that from other parts of Nigeria.

Investigating the Link between Early Life and Breast Anomalies

Several factors during childhood and adolescence are thought to be associated with the development of proliferative benign breast diseases and breast cancer in adulthood. In order to identify them, the authors conducted an extensive review of the literature up to October 2022, searching for clinical studies, reports, and guidelines in English. A thorough Medline/Pubmed and Google scholar database research was performed, investigating the link between diet, exercise, age of menarche, body mass index, ionizing radiation exposure during childhood and adolescence, and proliferative breast diseases and breast cancer in adulthood. A list of keywords, including breast disorders, adolescence, childhood, and breast cancer was included in our search algorithm. Numerous studies concede that the development of breast disease in adulthood is influenced by various risk factors, whose influence begins during early childhood and adolescence.

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.

When a Lump is More Than Just a Lump: Anaplastic Large Cell Lymphoma Presenting as a Pediatric Breast Mass

Anaplastic large cell lymphoma (ALCL) is a rare non-Hodgkin T-cell lymphoma characterized by a cluster of differentiation-30 positivity. Subtypes are characterized by positive or negative anaplastic lymphoma kinase (ALK) expression. ALCLs account for about 10% to 15% of all pediatric non-Hodgkin lymphomas and more than 90% of the cases are ALK-positive. We report a rare case of pediatric systemic ALK-negative ALCL with an atypical presentation as a painful breast mass. Despite the general benign features of most pediatric breast masses, it is important to consider malignant systemic diagnoses like the one reported here.

Comparison of emergency pediatric breast ultrasound interpretations and management recommendations between pediatric radiologists and breast imaging radiologists

PURPOSE

Pediatric patients with breast-related symptoms often initially present to the emergency department for evaluation. While pediatric radiologists are accustomed to evaluating acute infectious and traumatic etiologies, they may be less familiar with breast-specific findings. This study compares management recommendations of pediatric breast ultrasounds performed in the emergency setting between pediatric and breast imaging radiologists.

METHODS

This retrospective cohort study reviewed data from all pediatric breast ultrasounds performed in the emergency setting from a single academic institution from 1/1/14 to 12/31/19. During the study period, 12 pediatric radiologists with experience ranging from 1 to 33 years interpreted pediatric breast ultrasounds. Three breast imaging radiologists (with 3, 8, and 25 years of experience) retrospectively reviewed each case and recorded whether further management was recommended. Differences in recommendations were compared using Fisher's exact test. Cohen's kappa was used to assess agreement between subspecialty radiologists.

RESULTS

This study included 75 pediatric patients, with mean age 13 ± 5.6 years and malignancy rate of 1.3% (1/75). Pediatric radiologists and the most experienced breast imaging radiologist had moderate agreement in management recommendations (k = 0.54). There was no significant difference in recommendations for further management between pediatric radiologists (22/75 [29.3%]) and the most experienced breast imaging radiologist (15/75 [20.0%]), p = 0.26.

CONCLUSION

Recommendations for pediatric breast complaints in the emergency setting are comparable between subspecialties.

The CHEK2*1100delC Mutation and Adolescent Breast Cancer: A Case Report of Breast Cancer in a 19-Year-Old and a Review of the Literature

Background

Breast cancer (BC) is the most common non-skin cancer affecting women but is extremely uncommon in the adolescent population. Genetic inheritance has been linked to <10% of BCs. CHEK2 is an uncommon genetic variant with a reported incidence of 0.3-1.6% in the general population and 4.9-5.7% in those with a family history of BC. Commonly, this mutation presents in females of European descent and is rare in North America.

Case Presentation

A 19-year-old Caucasian female presented with breast pain and mass. She had an extensive family history of cancer, as well as a known CHEK2 gene mutation in 2 of her paternal aunts. Ultrasound and MRI confirmed a 4.5-cm mass with an enlarged right axillary lymph node. Image guided biopsy of the breast mass showed ER/PR-positive grade 1 invasive mucinous ductal cancer. Genetic testing confirmed an isolated CHEK2 mutation. After discussion by a multidisciplinary tumor board, the patient deferred bilateral mastectomy and underwent a right mastectomy with sentinel-lymph-node biopsy and immediate tissue-expander reconstruction. Final pathology confirmed ER/PR-positive Stage 1A (pT2 pN0 M0) invasive mucinous carcinoma. Chemotherapy was not recommended.

Summary

Malignant adolescent breast masses are relatively rare and CHEK2 does not typically present at younger than 20 years of age. While there are many different differential diagnoses when evaluating an adolescent with a breast mass, we wish to increase providers' suspicion of malignancy, specifically in those individuals who have a strong family history of BC and the CHEK2*1100delC mutation.

A Rare Case of Breast Malignancy in an Adolescent Woman: Lessons Learned from Diagnosis and Management

Introduction

Primary breast malignancy in adolescent women is very rare and differs in several aspects from findings in adult women.

Case Presentation

A young woman aged 16 years presented with a locally aggressive breast tumor. The patient received cisplatin-based chemotherapy followed by tumor resection assuming a diagnosis of germ cell tumor. Four months later, she developed locally recurrent disease and underwent a mastectomy. No definite diagnosis was agreed upon despite intensive pathological workup. Subsequent management consisted of follow-up only and the patient remains in complete remission 9 years later.

Conclusion

This case demonstrates the difficulty of diagnosis and management of rare malignancies in adolescents, and highlights the importance of international and interdisciplinary collaboration in diagnosis and clinical decision-making.

Mammary Fibrocystic Change in a Pre-Pubertal child- A Case Report with a Histopathological Perspective

Fibrocystic change in the breast is one of the entities under the spectrum of benign breast disease. It occurs primarily in females of the reproductive age group. Though the exact etiology is unknown, estrogen-progesterone imbalance is possibly one of the causative factors. Its occurrence in the pediatric age group is infrequent and is hitherto unreported in the pre-pubertal age group. Case report: We present the case of a 2-year-old female presenting with an ill -defined lump approximately 4 cm in diameter, with an unremarkable hormonal status for the age. Histopathology revealed fibrocystic change in the resected tissue. Conclusion: Fibrocystic breast change in children may represent an exaggeration of the normal developmental involution process.

Clinically Malignant Breast Lesion in an Adolescent Girl: A Case Report

Diseases of the breast in adolescent women are usually benign, and their treatment is simple using appropriate medical strategy and rarely surgical therapy. The whole team’s real challenge is when the girl presents malignant breast cancer symptoms such as a non-movable tumor, nipple discharge, nipple retraction, retraction of the skin, inflammatory infiltration of the breast, or ulceration. Presented here is a case of a 15-years-old girl with the features of a malignant neoplasm of the breast. There was an observed non-movable tumor, retraction of the nipple, inflammatory infiltration, and pain. The performed ultrasound and magnetic resonance imaging suggested a malignant lesion measuring 84 mm × 66 mm × 50 mm. After many diagnostic difficulties, the lesion evacuated spontaneously, and the abscess was diagnosed. In conclusion, not all features of a malignant breast tumor in adult women are typical for adolescent females. In young girls, breast diseases are usually benign, and appropriate diagnostics and therapy allow for an effective cure. Atypical breast lesions require the extraordinary cooperation of a multidisciplinary team.

Intracystic Papillary Breast Cancer in a 16-Year-Old Patient

BACKGROUND

Primary breast cancer in the pediatric population is rare. To our knowledge, no cases of intracystic papillary carcinoma have been reported in patients younger than 21 years.

CASE

A 16-year-old patient presented with a retroareolar mass and bloody nipple discharge in her left breast. A biopsy established papillary intracystic carcinoma. The patient was treated surgically and a risk reduction strategy developed in a multidisciplinary session was implemented.

Kikuchi Disease with enlargement of intramammary lymph node

We describe a rare case of intramammary lymphadenopathy due to Kikuchi-Fujimoto disease. A 15-year old female presented to the Breast Clinic with complaints of a tender, palpable right breast lump. An ultrasound of the area of concern demonstrated an enlarged 2.9 cm intramammary lymph node with preservation of the fatty hilum. An ultrasound guided core biopsy of the lymph node confirmed the diagnosis of Kikuchi-Fujimoto disease.

Isobaric Tags for Relative and Absolute Quantitation in Proteomic Analysis of Potential Biomarkers in Invasive Cancer, Ductal Carcinoma In Situ, and Mammary Fibroadenoma

OBJECTIVES

Breast malignancy is a serious threat to women's health around the world. Following the rapid progress in the field of cancer diagnostics and identification of pathological markers, breast tumor treatment methods have been greatly improved. However, for invasive, ductal carcinomas and mammary fibroadenoma, there is an urgent demand for better breast tumor-linked biomarkers. The current study was designed to identify diagnostic and/or therapeutic protein biomarkers for breast tumors.

METHODS

A total of 140 individuals were included, comprising 35 healthy women, 35 invasive breast cancers (IBC), 35 breast ductal carcinomas in situ (DCIS), and 35 breast fibroadenoma patients. Isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis was employed to characterize differentially expressed proteins for potential biomarkers in IBC, DCIS, and fibroadenomas by comparisons with their matched adjacent tissues and/or normal breast tissues. The public databases Metascape and String were used for bioinformatic analyses.

RESULTS

Using the proteomics approach, we identified differentially expressed proteins in tissues of different breast tumors compared to normal/adjacent breast tissues, including 100 in IBC, 52 in DCIS, and 44 in fibroadenoma. Among the 100 IBC differentially expressed proteins, 37 were found to be specific to this type of cancer only. Additionally, four proteins were specifically expressed in DCIS and four in fibroadenoma. Compared to corresponding adjacent tissues and normal breast tissues, 18 step-changing proteins were differentially expressed in IBC, 14 in DCIS, and 13 in fibroadenoma, respectively. Compared to DCIS and normal breast tissues, 65 proteins were differentially expressed in IBC with growing levels of malignancy.

CONCLUSIONS

The identified potential protein biomarkers may be used as diagnostic and/or therapeutic targets in breast tumors.

Benign Phyllodes Tumor in Children: A Study of 8 Cases and Review of the Literature

Phyllodes tumor (PT) occurs predominantly in middle-aged women, and although its occurrence in young women, adolescents, and even children is documented, presentation in the pediatric population has been the least well studied because of its rarity. Incompletely defined in children with PT are recurrence rates and optimal surgical management. We retrospectively studied the pathology database of Hartford Hospital from 2010 to 2017 to find all cases of PT in patients 18 years of age or younger. A series of 8 children/adolescents with breast masses diagnosed as benign PT were identified. Patients were 14 to 16 years of age (mean 15.2 y) and tumor size ranged from 2.2 to 7.2 cm (mean 4.4 cm). Both breasts were equally affected. All patients were treated with excision, tantamount to simple enucleation in most cases, and positive or "tumor-abutting" margins were universal. Mean follow-up after surgery was 27.5 months, during which time a single recurrence (at 9 mo) became manifest, which was re-excised and again showed benign PT. There were no pathologic features (including marginal status) that could have predicted the sole recurrence. Despite positive margins, the local recurrence rate for pediatric benign PT appears acceptably low (1 in 8 cases) such that reflex re-excision is probably unnecessary.

A population-based analysis of pediatric breast cancer

PURPOSE

The purpose of this study was to evaluate trends in demographics and outcomes of pediatric breast cancer in a United States population-based cohort.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was utilized to identify all pediatric patients with malignant breast tumors between 1973 and 2014. Analysis was performed using Stata Statistical Software version 13.1. Associations between categorical variables were made using X2 test. Log-rank test was used for univariate survival analysis. Kaplan-Meier analysis investigated five-year survival rates across several variables. Adjusted analysis was performed using a Cox Proportional-Hazards regression.

RESULTS

134 patients with breast malignancies were identified. Carcinoma was the most prevalent histology (48.5%), followed by fibroepithelial tumors (FETs) (35.1%), and sarcoma (14.2%). FETs were twice as common in black compared to nonblack patients (56.3% vs. 29.0%, p < 0.01). Analyzing histology by stage revealed that 100% of FETs were early stage disease (p < 0.0001). 46.7% of the tumors tested were ER/PR negative, more than twice as many compared to the published adult estimate of 20.0%. Unadjusted survival analysis revealed worse survival for patients with adenocarcinoma/sarcomas, advanced stage, and high grade disease, without a survival difference between races.

CONCLUSION

Breast cancer remains a rare malignancy among pediatric patients. Although black patients were found to have more noncarcinomatous tumors with less advanced disease, this did not confer a survival advantage.

TYPE OF STUDY

Retrospective cohort study.

LEVEL OF EVIDENCE

Level III.

A Prospective Observational Study of Breast Lumps in Adolescent Girls: Tertiary Care South Indian Teaching Hospital Experience

The aim of the current study was to assess the incidence and varying clinical presentations of benign breast lumps in adolescent age group in a Tertiary care Medical College Hospital. This was a prospective, observational study of 6-year duration (2011 to 2017) conducted in a Medical College, South India. All adolescent age group patients visiting the outpatient department (OPD) with complaints of breast lump were enrolled into the study. Triple assessment comprising of clinical examination, imaging, and core biopsy was used for diagnosis and identification of type of tumor. Management of tumors was based on pathology of core biopsy. During the study duration (2011 to 2017), a total of 15 pediatric patients of age between 11 to 14 years, presented with complaints of breast lumps. The most common symptom included painless lump in breast in 11 patients (73.34%). The histopathological examination (HPE) reported 12 cases (80%) as fibroadenomas and only 3 cases (20%) were phyllodes tumors. Based on the results of HPE, majority of the patients (53.34%) underwent circumareolar cosmetic incision. The most common lesions in pediatric age group are benign fibroadenomas; however, phyllodes are also not rare, and to manage them appropriately, they should be diagnosed preoperatively with core biopsy. Cases of malignancy, including phyllodes tumors, ductal adenocarcinomas, and metastatic lesions, have been documented in children and adolescents. Therefore, malignancy should be considered in the diagnosis of a pediatric and adolescent breast mass until formally ruled out.

Breast Lesions in Children and Adolescents: Diagnosis and Management

Pediatric breast disease is uncommon, and primary breast carcinoma in children is extremely rare. Therefore, the approach used to address breast lesions in pediatric patients differs from that in adults in many ways. Knowledge of the normal imaging features at various stages of development and the characteristics of breast disease in the pediatric population can help the radiologist to make confident diagnoses and manage patients appropriately. Most breast diseases in children are benign or associated with breast development, suggesting a need for conservative treatment. Interventional procedures might affect the developing breast and are only indicated in a limited number of cases. Histologic examination should be performed in pediatric patients, taking into account the size of the lesion and clinical history together with the imaging findings. A core needle biopsy is useful for accurate diagnosis and avoidance of irreparable damage in pediatric patients. Biopsy should be considered in the event of abnormal imaging findings, such as non-circumscribed margins, complex solid and cystic components, posterior acoustic shadowing, size above 3 cm, or an increase in mass size. A clinical history that includes a risk factor for malignancy, such as prior chest irradiation, known concurrent cancer not involving the breast, or family history of breast cancer, should prompt consideration of biopsy even if the lesion has a probably benign appearance on ultrasonography.

Surgical Treatment of Adolescent Breast Disorders: Institutional Experience and National Trends

STUDY OBJECTIVE

Adolescent breast disorders are rare and typically benign in nature; however, surgical treatments might require multiple surgeries. Because of the limited existing data, we sought to evaluate national trends and describe our institutional experience to help guide patient conversations.

DESIGN

Retrospective review.

SETTING

National database and academic institution.

PARTICIPANTS

Patients 20 years old or younger who underwent a breast procedure in the Kids' Inpatient Database from January 2000 to December 2012 and at Mayo Clinic-Rochester from January 2000 to July 2016. Conditions were categorized into common and complex breast disorders.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

To assess any trend of adolescent breast procedures across the United States as a whole, weighted Kids' Inpatient Database data were assessed using a Rao-Scott χ² test. Within the institutional data, the average number of procedures needed to correct common vs complex breast disorders were compared using an unequal variance t test.

RESULTS

In recent years, the estimated number of hospitalizations for breast procedures decreased in the United States from 1661 in 2000 to 1078 in 2012 (P < .001). At our institution, 241 patients underwent a breast procedure (75.1% [181/241] female) over 16 years. Common breast disorders were corrected with fewer procedures than complex breast disorders (mean 1.09 vs 2.22 procedures; P = .0003).

CONCLUSION

Inpatient treatment of adolescent breast disorders has been decreasing in recent years, likely reflecting a trend to outpatient procedures. Common adolescent breast disorders might be surgically corrected with 1 procedure, whereas complex disorders often require multiple surgeries to correct. It is important to discuss this with patients and their families to adequately set up expectations.

Analysis of factors predicting surgical intervention and associated costs in pediatric breast masses: a single center study

PURPOSE

Finding a breast mass in a child provokes apprehension in parents, especially in those with a family history of breast cancer. Clinicians must decide between serial imaging or biopsy of the mass. Herein, we identify management differences in those with and without a positive family history, as well as identify cost differences.

METHODS

An institutional retrospective review was performed of patients (2-18 years of age) with a diagnosis of breast mass. Patient demographics, presentation, medical and surgical history, physical exam, imaging, and pathologic diagnosis were collected. Cost data were acquired from the pediatric health information system (PHIS). Costs were compared between patients managed by biopsy versus serial ultrasounds. Bivariate analyses including Pearson's Chi-square, student's t tests, and logistic regression were performed.

RESULTS

The probability of biopsy increases with age (p = 0.0001) and female gender (p = 0.006). Biopsy rate is higher for larger masses (p < 0.0001), growing size (p < 0.0001), and in patients with a positive family history of breast cancer (p < 0.0001). The average cost of care for management with initial excisional biopsy was $4491 versus those with serial ultrasounds ($986) (p < 0.0001).

CONCLUSIONS

In patients with small lesions, even with a family history of breast cancer, non-operative monitoring is a safe and cost-effective alternative to invasive biopsy.

Clinical breast concerns in low-risk pediatric patients: practice review with proposed recommendations

BACKGROUND

Fibroadenoma is overwhelmingly the most common pediatric breast lesion. Breast malignancy is quite uncommon in children, most frequently metastatic or hematological malignancy. Core biopsy has largely replaced excision for diagnosis of breast masses in adults.

OBJECTIVE

The purpose of this study is two-fold: (1) compare utilization at our institution of interventional procedures vs. surgery for breast mass diagnosis in patients ≤18 years and (2) propose guidelines for breast imaging and biopsy in this population.

MATERIALS AND METHODS

We extracted data for all patients ≤18 who, between 2004 and 2016, underwent either (a) imaging and/or intervention procedure, or (b) breast surgery, from the Radiology Information System and Pathology Data System, respectively. We recorded age, gender, imaging, procedure, lesion size and histopathology.

RESULTS

We found 1,050 pediatric patients ≤18 years who underwent diagnostic breast ultrasound between 2004 and 2016. Of these, 168 patients underwent 199 interventional procedures. One hundred thirty patients underwent 160 core biopsies of solid lesions. Core biopsy pathology diagnosed benign lesions in 99%, of which 84.3% were fibroadenomas (n=135). One malignancy was diagnosed, B cell lymphoma. Two hundred three patients underwent surgical excision for 266 discrete lesions, and 89% were fibroadenomas. Seven benign phyllodes tumors were surgically diagnosed. No malignancies were diagnosed.

CONCLUSION

Core biopsy in patients 18 years and younger is well-tolerated, has few risks, and is preferable to surgery in developing breasts, but the goal is to avoid any breast procedure whenever possible. We propose guidelines for pediatric breast imaging, follow-up, core biopsy and excisions.

A case report of juvenile giant fibroadenoma of the breast: How common?

Breast lesions are rare prepubescents. The majority of breast lesions in this age group are benign. The most common of these rare lesions is juvenile fibroadenoma, which accounts for only 0.5% of all fibroadenomas. It is uncommon to have a palpable lesion in juveniles as very small lesions show obvious asymmetry. Fibroadenomas can grow to a large size, and surgical intervention is cosmetically challenging, especially in achieving symmetry in a developing breast. A 12-year-old girl presented with right breast swelling associated with tenderness. The mass had initially been small on self-discovery 1 year previously and grew with time. There was no overlying skin changes or any significant risk factors for breast malignancy. Triple assessment showed features of fibroadenoma, but we were unable to rule out a phyllodes tumor. She subsequently underwent excision biopsy of the right breast lesion for symptomatic control and histopathology examination (HPE) of the lesion. The HPE report confirmed the diagnosis of fibroadenoma. The patient recovered well postoperatively with no complications. Juvenile breast lesions are rare, and it is a challenge to provide an adolescent with the best treatment in terms of clinical and psychological care. A surgical approach requires meticulous planning to ensure a fine balance between adequate resection and the best cosmetic outcome for a developing breast.

Syndrome-Associated Tumors by Organ System

Certain tumors suggest the possibility of a patient harboring a genetic syndrome, particularly in children. Syndrome-associated tumors of the gastrointestinal tract, genitourinary tract, gynecologic tract, heart, lungs, brain, eye, endocrine organs, and hematopoietic system will be briefly discussed.

Analysis of surgically excised breast masses in 119 pediatric patients

PURPOSE

Breast masses in children and adolescents are uncommon and the vast majority are benign. There are currently limited analyses of breast masses in this population and clinical management is highly variable between institutions and providers. The purpose of our study is to analyze the demographics, pathology and management of 119 pediatric patients with breast masses; one of the largest studies to date.

METHODS

We performed a retrospective review of patients who underwent excision of a breast mass at a single pediatric center from June 2009 to November 2013. Demographics, imaging, pathology and management were reviewed.

RESULTS

Average patient age was 15.3 years, average mass size was 3.15 cm and 20.3 % had a family history of breast cancer. 68 % of patients had pre-operative ultrasound, and 31.9 % underwent a period of observation. The most common indication for resection was patient and family anxiety. All masses were benign, with fibroadenoma being the most common histopathology (75.2 %).

CONCLUSIONS

In our cohort there were no cases of malignancy. Only 31.9 % of patients underwent some form of observation and patient or family anxiety was the most common indication for proceeding with surgery. This suggests that patient anxiety may result in unnecessary operation. Our data may help reassure patients, families and providers that the risk of malignancy is low and could help develop more optimal management strategies.

Ultrasound of pediatric breast masses: what to do with lumps and bumps

The approach to breast masses in children differs from that in adults in many ways, including the differential diagnostic considerations, imaging algorithm and appropriateness of biopsy as a means of further characterization. Most pediatric breast masses are benign, either related to breast development or benign neoplastic processes. Biopsy is rarely needed and can damage the developing breast; thus radiologists must be familiar with the imaging appearance of common entities so that biopsies are judiciously recommended. The purpose of this article is to describe the imaging appearances of the normally developing pediatric breast as well as illustrate the imaging findings of a spectrum of diseases, including those that are benign (fibroadenoma, juvenile papillomatosis, pseudoangiomatous stromal hyperplasia, gynecomastia, abscess and fat necrosis), malignant (breast carcinoma and metastases), and have variable malignant potential (phyllodes tumor).