Phyllodes tumors may be benign or malignant. These tumors may reach a large size, distort the breast and the overlying the skin. In some cases, they lead to the necrosis of the skin and cause its ulceration. In these instances, they may fungate through the skin. However, the size or ulceration of the skin may not be used as criteria of malignancy. On gross inspection, these tumors have a white cut surface and show slits and clefts. Microscopically, they resemble the fibroadenomas and consist of a stroma and glanular structures. The only evidence of malignant behavior of tumor is the increased cellularity of the stroma, anaplastic changes and high number of mitosis in the stroma and invasion of the adjacent breast tissue. These findings, however, are not definite proof of a malignant outcome. The malignant lesions have a tendency to recur rather than to metastasize. In 15% of cases, however, the malignant lesions metastasize.