A Mother and Daughter With Phyllodes Tumors of the Breast

Giant Benign Mammary Phyllodes Tumor: Report of a Case and Review of the Literature

Phyllodes tumor of the breast is an infrequently encountered fibroepithelial neoplasm, which accounts for 0.3–1% of all tumors. Few case reports have described the occurrence of giant phyllodes tumor. To our knowledge, about 20% of phyllodes tumors would be considered giant benign. Complete surgical excision is the standard of care for giant benign phyllodes tumors; axillary lymph node metastasis is rare, and dissection should be limited to patients with pathologic evidence of tumor in the lymph nodes. We report the case of a 40-year-old Mexican woman with giant mammary tumor who underwent a right total mastectomy. The pathology results showed a benign phyllodes tumor 4,857 g in weight and 40.2 × 36.3 × 15 cm in size. We do not suggest adjuvant radiation therapy for patients with benign phyllodes tumors that are widely excised. A review of the pertinent literature was performed.

Germline Genetic Mutations in a Multi-center Contemporary Cohort of 550 Phyllodes Tumors: An Opportunity for Expanded Multi-gene Panel Testing

BACKGROUND

A paucity of data exists regarding inherited mutations associated with phyllodes tumors (PT); however, some are reported (TP53, BRCA1, and RB1). A PT diagnosis does not meet NCCN criteria for testing, including within Li-Fraumeni Syndrome (TP53). We sought to determine the prevalence of mutations associated with PT.

METHODS

We performed an 11-institution review of contemporary (2007-2017) PT practice. We recorded multigenerational family history and personal history of genetic testing. We identified patients meeting NCCN criteria for genetic evaluation. Logistic regression estimated the association of select covariates with likelihood of undergoing genetic testing.

RESULTS

Of 550 PT patients, 59.8% (n = 329) had a close family history of cancer, and 34.0% (n = 112) had ≥ 3 family members affected. Only 6.2% (n = 34) underwent genetic testing, 38.2% (n = 13) of whom had only BRCA1/BRCA2 tested. Of 34 patients tested, 8.8% had a deleterious mutation (1 BRCA1, 2 TP53), and 5.9% had a BRCA2 VUS. Of women who had TP53 testing (N = 21), 9.5% had a mutation. Selection for testing was not associated with age (odds ratio [OR] 1.01, p = 0.55) or PT size (p = 0.12) but was associated with grade (malignant vs. benign: OR 9.17, 95% CI 3.97-21.18) and meeting NCCN criteria (OR 3.43, 95% confidence interval 1.70-6.94). Notably, an additional 86 (15.6%) patients met NCCN criteria but had no genetic testing.

CONCLUSIONS

Very few women with PT undergo germline testing; however, in those selected for testing, a deleterious mutation was identified in ~ 10%. Multigene testing of a PT cohort would present an opportunity to discover the true incidence of germline mutations in PT patients.

Phyllodes Tumors of the Breast: A Literature Review

Phyllodes tumors (PTs) of the breast are considered a rare fibroepithelial neoplasms of the breast and are considered a challenging for both pathologists and surgeons. The World Health Organization (WHO) has classified PTs histologically as benign, borderline, and malignant. PTs can be detected in all ages; however, the median age of presentation is 45 years. PTs can mimic fibroadenoma in clinical presentations. Breast imaging is also similar to fibroadenomas. Cytological diagnosis of PTs by biopsy is usually unreliable. However, a core needle biopsy is superior to fine-needle aspiration. Surgery is considered the mainstay treatment for PTs of the breast with a goal of achieving negative margins. Adjuvant chemotherapy and radiation therapy use for malignant PTs are controversial.

Recurrent Phyllodes Tumour of the Breast Transforming to a Fibrosarcoma

Phyllodes tumours of the breast are characterized by having both an epithelial as well as stromal component and these usually comprise almost 3% of all fibroepithelial tumours. They are exceptional in this aspect to convert into a stromal sarcoma of the breast after multiple recurrences. To the best of our knowledge, there are only three case reports regarding this in the available literature as it is an exceptional change. In this case report, we present a case of recurrent phyllodes transforming into a breast fibrosarcoma in a middle age postmenopausal woman. Histopathological examination and immunohistochemistry of the lesion were performed to confirm the diagnosis of breast fibrosarcoma.

Fibroepithelial lesions of the breast: a comprehensive morphological and outcome analysis of a large series

Mammary fibroepithelial lesions encompass a wide spectrum of tumors ranging from an indolent fibroadenoma to potentially fatal malignant phyllodes tumor. The criteria used for their classification based on morphological assessment are often challenging to apply and there is no consensus as to what constitutes an adequate resection margin. We studied a retrospective cohort of 213 fibroepithelial lesions in 178 patients (80 fibroadenomas with unusual features and 133 phyllodes tumors: 63 benign, 41 borderline, and 29 malignant) in order to describe the spectrum of changes within each group, with special emphasis on margin evaluation. Outcome data were available for 153 fibroepithelial lesions in 139 patients (median 56 months, range 3-249 months). Positive final margin (tumor transected), age < 50 years and a predominantly myxoid stroma were statistically significant predictors of local recurrence, while age > 50, stromal overgrowth, diffuse marked atypia, necrosis and mitotic index of ≥ 10 per 10 HPF were predictive of distant metastases. Tumors with satellite/bulging nodules were at a significantly higher risk to have a final positive resection margin. Our findings highlight important aspects of the interpretation and reporting of fibroepithelial lesions: the amount of myxoid stroma and the presence of satellite nodules are clinically relevant and should be routinely assessed and reported; infiltrative border might not be a prerequisite for the diagnosis of malignant phyllodes tumor, while the presence of tumor necrosis, massive stromal overgrowth or mitotic index of ≥ 25 per 10 HPF is diagnostic of malignant phyllodes tumor. On the other hand, increased mitotic index outside of the range of the World Health Organization guidelines in the absence of other worrisome features should be treated with caution, as it can be found in benign tumors.

Phyllodes tumors of the breast in 2 sisters: Case report and review of literature

RATIONALE

Phyllodes tumors (PT) of the breast are rare neoplasm originating from fibroepithelial component. To our knowledge, our report is the first reported case of PT in 2 sisters.

PATIENT CONCERNS

We presented 2 cases of PT of the breast involving in 2 sisters. On physical examination of the younger sister, a firm mass measuring approximately 3 cm in diameter was identified in upper inner quadrant of the right breast. Physical examination of the elder sister revealed a 3 cm lump in upper outer quadrant of the left breast.

DIAGNOSES

Histopathology of the younger sister revealed a malignant PT. The elder sister was diagnosed with borderline PT.

INTERVENTIONS

The younger sister with malignant PT underwent right mastectomy. The elder sister with borderline PT was scheduled for wide resection of the mass in the left breast.

OUTCOMES

After a follow-up of 23 months, no local or distant recurrence was observed.

LESSONS

Our cases indicate that genetic factor may contribute to the risk of PT of the breast. Markers such as p53 and Ki-67 may have some correlation with PT malignancy.

Fibroepithelial lesions; The WHO spectrum

Fibroepithelial lesions of the breast comprise a morphologically and biologically heterogeneous group of biphasic tumors with epithelial and stromal components that demonstrate widely variable clinical behavior. Fibroadenomas are common benign tumors with a number of histologic variants, most of which pose no diagnostic challenge. Cellular and juvenile fibroadenomas can have overlapping features with phyllodes tumors and should be recognized. Phyllodes tumors constitute a spectrum of lesions with varying clinical behavior and are graded as benign, borderline or malignant based on a set of histologic features according to recommendations by the World Health Organization (WHO). Recent developments have significantly expanded our understanding of the pathogenesis of fibroepithelial lesions, highlighting fibroadenomas as true neoplasms and underscoring a commonality with phyllodes tumors in the form of recurrent MED12 exon 2 mutations. In addition, sequencing studies have elucidated pathways associated with phyllodes tumor progression. Accurate diagnosis and grading of phyllodes tumors are important for patient management and prognosis, as grade broadly correlates with increasing local recurrence risk, and essentially only malignant tumors metastasize. However, classification of fibroepithelial lesions in many cases remains challenging on both core biopsy and excision specimens. A commonly encountered problem at the benign end of the spectrum is the distinction of benign phyllodes tumor from cellular fibroadenoma, which is largely due to the subjective nature of histologic features used in diagnosis and histologic overlap between lesions. Grading is further complicated by the requirement to integrate multiple subjective and ill-defined parameters. On the opposite end of the histologic spectrum, malignant phyllodes tumors must be distinguished from more common metaplastic carcinomas and from primary or metastatic sarcomas, which can be especially difficult in core biopsies. Immunohistochemistry can be useful in the differential diagnosis but should be interpreted with attention to caveats. This review provides an overview and update on the spectrum of fibroepithelial lesions, with special emphasis on common problems and practical issues in diagnosis.

Phyllodes tumours of the breast: a consensus review

Phyllodes tumours constitute an uncommon but complex group of mammary fibroepithelial lesions. Accurate and reproducible grading of these tumours has long been challenging, owing to the need to assess multiple stratified histological parameters, which may be weighted differently by individual pathologists. Distinction of benign phyllodes tumours from cellular fibroadenomas is fraught with difficulty, due to overlapping microscopic features. Similarly, separation of the malignant phyllodes tumour from spindle cell metaplastic carcinoma and primary breast sarcoma can be problematic. Phyllodes tumours are treated by surgical excision. However, there is no consensus on the definition of an appropriate surgical margin to ensure completeness of excision and reduction of recurrence risk. Interpretive subjectivity, overlapping histological diagnostic criteria, suboptimal correlation between histological classification and clinical behaviour and the lack of robust molecular predictors of outcome make further investigation of the pathogenesis of these fascinating tumours a matter of active research. This review consolidates the current understanding of their pathobiology and clinical behaviour, and includes proposals for a rational approach to the classification and management of phyllodes tumours.