Periductal stromal tumor (PDST) is a rare biphasic tumor of the breast that exhibits low-grade malignancy and intermediate behavior. It is characterized by proliferation of atypical spindle cells surrounding benign mammary ducts and infiltrating adjacent adipose tissue. PDST is distinguished from phyllodes tumor by its lack of leaf-like architecture; however, it is still unclear whether PDST is a separate entity or a certain spectrum of phyllodes tumor. Phyllodes tumors constitute a group of rare epithelial lesions of the breast which mainly develops at around 40-50 years. The histologic characteristics to be considered are many and often heterogeneous in the same lesion which makes interpretation in needle biopsy material difficult. Most phyllodes tumors have a benign nature, with a high rate of postsurgical recurrence. In the malignant form, metastases are described by distant hematogenous route; its indolent behavior implies a tight surgical management with precise excision of the lesion even if there is not, however, a unanimous consent on the parameters of accuracy of the margins.
Keywords: US; breast; breast surgery; carcinoma; follow-up; mammography; periductal stromal tumor; phyllodes tumor.
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