Diagnostic radiation oncology: malignant cystosarcoma phylloides

Cystosarcoma phylloides is a rare, mostly benign tumor of the breast. In most cases curative treatment is possible with complete surgical excision of the lesions. However, there is a high local recurrence rate up to 46%. There are only few reported successful treatments with radiotherapy in cystosarcoma phylloides. Radiotherapy is indicated in patients with locoregional recurrent disease and those with symptomatic metastases.

We present a case of a 54-year-old woman with a painless mass in the right breast. Clinical examination showed a large, firm tumor and axillary lymph node metastases. The patient underwent mastectomy and axillary lymph node dissection. Histopathology showed a cystosarcoma phylloides measuring 30 x 25 x 19 cm as well as lymph node metastases measuring 9.5 cm. Despite a R0 resection the patient developed 4 thoracic wall recurrences within 2 years. At 18 months there were additional multiple pulmonary and pleural lesions with a maximum diameter of 6.5 cm. Subsequently the patient received polychemotherapy. There was a significant response of the thoracic wall disease as well as of the pulmonary and pleural lesions. Six months later there was further progress of the thoracic wall disease and the pulmonary lesions. Following this the patient underwent radiation therapy of her right thoracic wall with 50 Gy which lead clinically to a quick response. For the past 5 months there has been no evidence of thoracic wall disease recurrence.

This is an unusual case of cystosarcoma phylloides and response to different therapeutic modalities. Cystosarcoma phylloides showed to be a radiosensitive tumor. Thus postopertive radiation therapy is indicated to prevent local recurrences.