Prognostic indicators in cystosarcoma phylloides.

Cystosarcoma phylloides is a breast neoplasm that has a frequently unpredictable clinical course. We made a retrospective study of 25 patients with this disease in an attempt to evaluate the indicators of aggressive behavior. In our series, older patient age, nulliparity, rapid tumor growth, pain, and large size of tumors increased the suspicion of malignancy but were not always reliable indicators of malignancy. Skin ulceration, tumor necrosis, and infiltrating tumor margins were the most ominous characteristics. High-grade tumors, that is, those with increased cellularity, vascularity, mitotic figure, and pleomorphism, often indicated aggressive behavior. Mixed mesenchymal components were sometimes related to a malignant course. We found a 24 percent incidence of associated breast cancer. Carcinoma of the ipsilateral breast was found in four patients and later in the contralateral breast in two patients. Of our 25 patients, 10 (40 percent) had recurrence and 4 (16 percent) died from disease. Recurrences after treatment usually occurred within 3 years. Patients must be followed carefully for local recurrence or metastases, since the clinical course is not predictable. Forty percent of the lesions were diagnosed as being malignant. Local excision was associated with recurrence in six of eight patients and was clearly inadequate treatment. Quadrantectomy was effective for benign peripheral lesions when a generous margin could be obtained. From these data, we believe that mastectomy is indicated in all patients with malignant lesions and in those with large benign lesions.