Spindle-Cell Lesions of the Breast with Emphasis on the Differential Diagnosis

Compared to epithelial lesions, spindle-cell lesions of the breast are relatively uncommon and, because of that, may cause diagnostic difficulty. The majority of these spindle cell lesions, such as fibromatosis, nodular fasciitis, spindlecell carcinoma, inflammatory myofibroblatic tumor and angiosarcoma, resemble their more common non-mammary counterparts. A few others, such as pseudoangiomatous stromal hyperplasia for example, specifically arise in breast. This review discusses these mammary spindle cell lesions with a focus on their salient histological features.