Background: Cystosarcoma phyllodes (CP) is a rare neoplasm of the breast. Many studies of the histology of CP have been reported. However, few reports have included an evaluation of the histologic appearance of pulmonary metastases, or the change in histologic grade as a function of time in patients with recurrent tumors.
Methods: We treated two patients with pulmonary metastases, CP from 1973 to 1995. One patient died of respiratory failure. The other underwent six operations for CP. We evaluated the histologic characteristics of these metastases and changes in the histologic grade of recurrent tumors.
Results: The primary lesions in these two cases were typical high-grade malignant tumors. Case 1 had multiple pulmonary metastases and histologic findings indicated typical malignant CP. Case 2 had a solitary pulmonary metastasis and histologic findings showed low-grade malignant CP, which could be resected. The first patient died of respiratory failure ten months after surgery. The second had no further pulmonary metastases although she had frequent local recurrences, and the histologic features of these tumors became progressively worse.
Conclusion: We suggest that patients with malignant CP be followed closely and that when pulmonary metastases are detected, they should be resected if possible, because pulmonary metastatic tumors may represent lower-grade malignant CP.