Case 9: Malignant Phyllodes Tumor of the Breast
Authors: Sakshi Andersen, Matilda Svenning Hunt & Tine M. Engberg Damsgaard
A 58-year-old female was referred to the Department of Breast Surgery with a red, swollen and tender right breast. The patient had a medical history of hypertension and benign cysts in the breasts and had undergone augmentation mammoplasty with breast implants 15 years ago. The symptoms debuted 14 days prior to admission, and she was initially treated with antibiotics on the suspicion of an infection. The patient had not at any time presented with fever or any other symptoms of illness. According to the patient, no mass in the breast could be palpated initially.
Before and after
Patient examination
Inspection and palpation of the right breast revealed a giant mass, which was estimated to be 12 cm in diameter, located behind the nipple-areola complex. The skin was stretched, and the shape of the breast was deformed. The contralateral breast was unaffected. No enlarged lymph nodes were found in the axillary region or the head and neck region. Nine days after the initial examination, the mass was clinically assessed to have enlarged to 30 cm in diameter.
Pre-Operative Considerations
An ultrasound was performed immediately and showed a large heterogenous mass in the right breast involving almost all of the breast with no clear arguments of invasion, classified as BIRADS 5. The breast implant was with extracapsular rupture on the right side, and the breast implant on the left side was with intracapsular rupture. The diagnosis of malignant phyllodes tumor was suspected. Hence, a mammography was substituted with an MRI-scan of the breasts, and subsequently a PET-CT scan. Furthermore, a core needle biopsy of the breast was performed which showed a borderline phyllodes tumor. Malignant phyllodes tumor of the breast is a rare type of cancer that arises from the connective tissue of the breast. It accounts for 0.3 to 1% of all breast cancers (1). Phyllodes tumors are classified into three categories: benign, borderline and malignant based upon the microscopic appearance of the stromal component with a distribution of 60%, 20%, and 20%, respectively (2). Treatment of malignant phyllodes tumor typically involves complete surgical resection of the tumor with a margin of normal breast tissue, with axillary lymph node dissection being reserved for selected cases. Adjuvant radiation therapy may be considered in certain situations such as positive margins or large tumors to reduce the risk of local recurrence. In a multidisciplinary team including the sarcoma team, breast surgeons and plastic surgeons, it was decided to perform resection of the tumor with a 2 cm resection margin without primary breast reconstruction. Depending on the defect after radical excision the following options for closure were considered: 1) split- or full-thickness skin graft 2) a thoraco-abdominal rotation flap or 3) a latissimus dorsi muscle flap.
Step 1: Pre-operative imaging
A) MRI-scan and B) PET-CT-scan revealed a tumor measuring 12x12x13 cm in diameter with no deep invasion of the pectoralis muscle and several pathological looking lymph nodes in the left axilla and in the subpectoral area.
Step 2: First step of excision
The surgery was initiated by the breast surgeon with a wide incision around the right mamma. Four lymph nodes from the right axillary region were resected and showed no evidence of malignancy with peroperative frozen section analysis.
- Notice the design of the thoraco-abdominal flap marked on the lateral side of the abdomen.
Step 3: Radical mastectomy
The radical mastectomy was performed in the subcutaneos cleavage to the pectoralis muscle.
Step 4: Explantation of the breast implant
The sarcoma surgeon resected both the major an the minor pectoralis muscles and explanted the right breast implant.
- Notice the breast implant in the center of the image.
Step 5: Further excision
The breast, including the pectoralis muscles were excised.
- Notice the costae in the depth of the excision
Step 6: Post-excision defect
The defect measured 25 x 30 cm. Two drains were inserted. Primary closure was performed by undermining adjacent tissue. The defect was closed in three layers with vicryl and with nylon.
Step 7: Closure and seven days postoperative
The result of the primary closure seven days postoperative.
Post-Operative Plan
The final pathology diagnosis confirmed a malignant phylloides tumor and four lymph nodes with no malignancy. Follow-up is planned with MRI-scans and PET-CT scans every third month in at least five years in the sarcoma section. The patient is awaiting secondary breast reconstruction.
- 1) The gold standard for treatment of phyllodes tumor is surgical excision with clear margins. However, these recommendations are based on case-reports due to the low incidence of the disease.
- 2) Early detection and correct diagnosis are essential since all cases should be evaluated in a multidisciplinary team with a minimum of delay until treatment.
- 3) Decision on primary or secondary breast reconstruction should be evaluated case-by-case. Current literature does not suggest a higher recurrence rate after primary breast reconstruction.
- 1) Although most phyllodes tumor of the breast are benign, distinction between benign, borderline and malignant phyllodes tumors impose a challenge.
- 2) Presurgical diagnosis of phyllodes tumor is difficult since fine needle aspiration cytology has low sensitivity and specificity in detecting phyllodes tumor. A core needle biopsy is preferred, but it is not accurate in differentiating between fibroadenoma and phyllodes tumor. However, postoperative re-classification often occurs.
References
- Lissidini G, Mulè A, Santoro A, Papa G, Nicosia L, Cassano E, Ashoor AA, Veronesi P, Pantanowitz L, Hornick JL, Rossi ED. Malignant phyllodes tumor of the breast: a systematic review. Pathologica. 2022 Apr;114(2):111-120. doi: 10.32074/1591-951X-754.
- Rodrigues MF, Truong PT, McKevitt EC, Weir LM, Knowling MA, Wai ES. Phyllodes tumors of the breast: The British Columbia Cancer Agency experience. Cancer Radiother. 2018 Apr;22(2):112-119. doi: 10.1016/j.canrad.2017.08.112.