Which of the following statement(s) is/are correct concerning cystosarcoma phyllodes?

c. Axillary lymph node dissection is not necessary for malignant cystosarcoma phyllodes

Cystosarcoma phyllodes is a tumor arising in the mesenchymal tissue of the breast. The tumors usually present as a painless breast mass. Phyllodes tumor is most commonly encountered in women age 30–40 years of age but can occur at any age, even before puberty. The differentiation of a benign from a malignant phyllodes tumor may be difficult. About one-fourth of all phyllodes tumors are histologically malignant, but only a fraction of these patients actually develop metastatic disease. The optimum treatment for benign or malignant phyllodes tumor is wide excision with a margin of normal breast tissue. The margin must be histologically free of involvement because even benign lesions can recur after incomplete excision. If this can be done leaving an adequate cosmetic appearance, mastectomy is not necessary. Total mastectomy is reserved for large lesions in small-breasted women or recurrences after previous local excision that is not amenable to repeat local excision. Axillary lymph node dissection is not performed in the absence of biopsy-proven nodal involvement, even for malignant phyllodes tumors, because axillary metastases are uncommon.