What is the diagnosis and treatment for recurrent phyllodes tumors?

Diagnosis of Recurrent Phyllodes Tumors

For recurrent phyllodes tumors, diagnosis requires clinical examination, imaging with ultrasound and mammography, and tissue sampling with histology preferred over cytology, followed by chest imaging to exclude metastatic disease. 1

Clinical Presentation

The hallmark of recurrent phyllodes is a locally recurrent breast mass after previous excision, typically presenting as a rapidly enlarging, usually painless lump in the same breast. 2 The mean time to local recurrence is approximately 20 months, though malignant subtypes tend to recur earlier. 3

Diagnostic Workup Algorithm

When a patient presents with suspected recurrence after phyllodes excision, proceed systematically:

1. Clinical Assessment

• History and physical examination focusing on the previous surgical site, looking specifically for a palpable mass and documenting growth rate. 1
• Document the original tumor subtype (benign, borderline, or malignant) and prior surgical margin status, as 10 of 11 locally recurrent tumors had positive or ≤1 mm margins at initial surgery. 4

2. Imaging Studies

• Ultrasound is mandatory as the primary imaging modality. 1
• Mammogram for all patients to evaluate the entire breast and contralateral side. 1
• Chest imaging should be considered to screen for distant metastases, particularly in borderline and malignant subtypes. 1

3. Tissue Diagnosis

• Tissue sampling with histology is preferred over fine needle aspiration or core biopsy. 1
• Core needle biopsy may not reliably distinguish recurrent phyllodes from other lesions, as it cannot adequately sample the characteristic leaf-like architecture. 2, 5
• Excisional biopsy provides definitive diagnosis when core biopsy is indeterminate. 2

4. Metastatic Evaluation

The workup must determine whether the recurrence is local only or associated with metastatic disease, as this fundamentally changes management. 1

• If no metastatic disease is found: proceed to re-excision with wide margins without axillary staging. 1
• If metastatic disease is detected: manage according to soft tissue sarcoma principles per NCCN Guidelines, as distant metastases (most commonly to lung) occur in approximately 20% of malignant phyllodes and carry poor prognosis. 1, 6, 7

Critical Diagnostic Pitfalls

• Do NOT rely on core needle biopsy or FNA alone to exclude recurrent phyllodes in a rapidly growing breast mass, as these may miss the diagnosis. 2, 5
• Do NOT assume benign behavior based on original histology: 19% of patients can develop malignant recurrence from initially benign or borderline tumors. 3
• Do NOT perform routine axillary staging as phyllodes tumors rarely metastasize to lymph nodes—this adds unnecessary morbidity without benefit. 1, 2, 5, 7

Histopathological Considerations

Recurrent tumors are usually histologically similar to the initial tumor, but malignant transformation can occur in 19% of cases initially classified as benign or borderline. 3 The diagnostic challenge is particularly significant when spindle cell-predominant patterns are present, which may be misdiagnosed as sarcomatoid carcinoma. 2

Treatment Planning After Diagnosis

Once recurrence is confirmed without metastatic disease:

• Re-excision with wide margins (≥1 cm) without axillary staging is the definitive treatment. 1, 2
• Consider postoperative radiation therapy (category 2B) if additional recurrence would create significant morbidity, such as chest wall recurrence after salvage mastectomy, following soft tissue sarcoma principles. 1, 5
• Radiotherapy should be specifically considered for large tumors (>5 cm), infiltrative margins, or cases where clear margins could not be achieved despite re-excision attempts. 5

Multidisciplinary Management

Borderline and malignant recurrent phyllodes tumors should be referred to specialist sarcoma centers for pathology review and multidisciplinary team discussion to ensure appropriate risk stratification and treatment planning. 2, 5