Clinical course of cystosarcoma phyllodes related to histologic appearance.

A series of 17 females having cystosarcoma phyllodes underwent surgical treatment. The subsequent clinical course was observed periodically. Twelve patients had originally histologically benign tumors. Six patients had a recurrence, and of these, malignant characteristics developed in four instances. Five patients had originally histologically malignant tumors. Recurrences were encountered in four. Five patients died from a generalized spread of the tumor. Three of these patients had originally histologically benign tumors, in which malignant features of the recurrent tumor subsequently developed. The surgical treatment ranged from local excision to simple mastectomy with additional roentgenotherapy in three. Neither procedure prevented a recurrence from the original tumor, whether benign or malignant. Poor correlation exists between biologic behavior and histologic appearance of cystosarcoma phyllodes, independent of the surgical procedure. Wide local excision in histologically benign and mastectomy in histologically malignant tumors are advised, but no final decision could be reached. It is proposed to restrict ther term cystosarcoma phyllodes to histologically malignant tumors and use the term fibroadenoma phyllodes in instances of histologically benign tumors.