From the Guidelines
Phyllodes tumors of the breast should be treated with wide local excision with tumor-free margins of 1 cm or greater, regardless of their subtype, as this approach has been shown to reduce the risk of local recurrence 1.
Pathological Characteristics
Phyllodes tumors are rare fibroepithelial breast neoplasms characterized by a leaf-like architecture and varying degrees of malignant potential. They are classified as benign, borderline, or malignant based on several histological features, including stromal cellularity, stromal atypia, mitotic activity, tumor borders, and stromal overgrowth.
- Malignant phyllodes tumors show marked stromal cellularity, significant nuclear atypia, high mitotic rates, infiltrative margins, and stromal overgrowth.
- The epithelial component is typically benign across all grades.
- Immunohistochemically, these tumors often express CD34 and may show p53 mutations in malignant cases.
Diagnosis and Treatment
Accurate pathological assessment is crucial as it guides treatment decisions.
- Clinical suspicion of phyllodes tumor is raised by a palpable mass, rapid growth, large size, and imaging suggestive of fibroadenoma except for size and/or history of growth.
- Ultrasound and mammogram are used for diagnosis, but fine needle aspiration (FNA) cytology and core needle biopsy are often inadequate to distinguish phyllodes tumors from fibroadenoma 1.
- Wide local excision with at least 1 cm margins is the standard surgical approach for all phyllodes tumors, as narrow surgical margins are associated with heightened local recurrence risk 1.
- Axillary staging or axillary lymph node dissection is not necessary unless the lymph nodes are pathologic on clinical examination.
- In patients who experience a local recurrence, resection of the recurrence with wide tumor-free surgical margins should be performed.
From the Research
Phyllodes Breast Cancer Pathology
- Phyllodes tumors are rare fibroepithelial tumors of the breast, with a range of histological subtypes including benign, borderline, and malignant 2, 3, 4.
- The mainstay of treatment for phyllodes tumors is surgical excision with a safe margin, with breast-conserving surgery being a viable option for many patients 3, 4.
- Adjuvant radiation therapy (RT) may be beneficial in improving local recurrence-free survival (LRFS) in patients with borderline or malignant phyllodes tumors, particularly those with margin-negative wide local excision 2, 5.
- However, the role of adjuvant RT in phyllodes tumors is still unclear, and its use should be considered on a case-by-case basis 2, 6.
- Chemotherapy may also be effective in treating metastatic phyllodes tumors, with a combination of cisplatin, nab-paclitaxel, and liposomal doxorubicin showing promise in one case report 5.
- Tumor grade, size, and margin status are significant risk factors for local recurrence and poor outcomes in phyllodes tumors 3, 4.
- Infiltrative tumor borders may also be associated with increased local recurrence risk, and may be used in conjunction with margin status to assess risk 4.
- Overall, the prognosis for phyllodes tumors is generally good, with 5-year survival rates ranging from 82-100% depending on histological subtype and treatment outcomes 2, 4, 6.