Background

Malignant phyllodes tumor of breast is a rare tumor type with a high risk of recurrence and metastasis. The lungs is the most common metastatic site of this kind of tumor. The prognosis of patients varies greatly. At present, there is no consensus on clinical treatment. This study reports a rare case of malignant phyllodes tumor of breast with early metastasis, whose disease progressed rapidly and the clinical outcome is very poor despite undergoing expansion of resection, radiotherapy, local perfusion chemotherapy, and immune-targeted therapy.

Case presentation

A 59-year-old female patient presented in July 2021 for a huge palpable lump measuring 16.0 cm × 9.0 cm × 6.0 cm in her left breast a month earlier. There were no abnormal findings in the patient or family records. Based on the result from pathological examination, the lesion was identified as malignant phyllodes tumor. The patient then underwent modified radical mastectomy for left breast cancer on July 14, 2021. Postoperative pathological and immunohistochemical evaluation confirmed a malignant phyllodes tumor of the left breast accompanied by hemorrhage, necrosis, and cystic degeneration. The Vessels and the nerves were not seen to be involved, so as the nipples, the skin, and the axillary lymph nodes (0/18). Immunohistochemical results revealed that ER-, PR-, HER-2-, and the expression of Ki67 was 70%. The patient received traditional Chinese medicine treatment after operation but not radiotherapy and chemotherapy. About one and a half months later, the patient was found to have multiple nodules on her left chest wall. The nodules were tough, with unclear boundaries and no obvious tenderness. The largest nodule is about 10.0 cm × 4.0 cm. Computerized tomography of chest showed that there are ground-glass opacities in the upper lobe of the left lung. The left chest wall is thickened. There are multiple mass-occupations in the left chest wall and axilla, suggesting tumor recurrence. Additionally, ultrasonography revealed that there are many hypoechoics in the left mammary gland tissue with unclear boundary and irregular morphology. Among which the largest was 10.2 cm × 3.9 cm (BI-RADS 5). There is a 1.7 cm × 0.9 cm inhomogeneous echo with clear boundary in the left armpit. Because the local lesions of the patient grew rapidly and showed signs of rupture, the patient underwent the left chest wall lesion excision and fascial flap transplantation on September 23, 2021. During the operation, the masses appeared viscous and liquid, and distributed in many tissues such as subcutaneous and muscle. The postoperative pathological results were the same as the previous. No lesions were observed at the cutting edge, basal and skin margin. Immunohistochemical results showed ER-, PR-, Bcl-2-, Ki67 60%, PHH3+, P63-, CK5/6-. Two weeks later, we found nodular eminences at the edge of the resection area with rapid growth. Local ulceration occurred on the skin surface due to this rapid growth. Jelly-like substance flowed out of the local incision suggesting that the tumor may have relapsed. We performed local lavage with lobaplatin during dressing change at the incision, but the mass continued to grow rapidly, so the patient underwent the left chest wall lesion excision and fascial flap transplantation again on November 2, 2021. Then she underwent local radiotherapy after consultation. Radiation dose: left supraclavicular area + left chest wall: 20 Gy/10 times/14 days; left chest wall metastases: 24 Gy/10 times/14 days. Sintilimab was given intravenously during radiotherapy (200 mg/3 weeks). However, the metastases in the left chest wall of the patient continued to increase which indicates the tumor is not sensitive to radiotherapy and immunotargeted therapy, so the treatment regimen was halted. The patient was discharged. Afterwards, according to the information obtained from the patient's family, her condition progressed rapidly and she died of multiple organ failure 3 months later.

Conclusion

In this case, it took about 6 months from the onset of phyllodes tumor to the death of the patient. During this period, local recurrence and pulmonary metastasis occurred several times, and the prognosis was extremely poor. At present, there are no standardized therapy in clinical practice, nor effective biomarkers for predicting prognosis. Preoperative systemic treatment may be helpful for effective management of malignant lobular tumors. In-depth analysis of genetic changes may shed light on the pathogenesis and progression and potentially help to recognize appropriate treatment strategies.