Nodular fasciitis of the breast

Abstract

Nodular Fasciitis in the breast is a rare pathology, categorized as a benign mesenchymal-origin breast tumor, with higher prevalence in middle-aged women. Its diagnosis is complex due to its low incidence and non-specific clinical presentation. However, although some authors suggest that microtrauma may be the origin, most patients do not report a history of trauma in the affected area. The pathology presents as a firm, painless, or slightly painful nodule that simulates breast cancer, typically located in the upper-outer quadrant (UOQ). The most common diagnostic tests are Mammography, which shows a dense and irregular nodule, and Ultrasound, which reveals a hypoechoic lesion with irregular margins. Excisional biopsy is the most commonly used procedure, with microscopic findings such as fibroblasts and frequent mitosis without atypia. A less invasive treatment is vacuum-assisted ultrasound-guided excision, although in some cases, a “wait and see” approach may be chosen due to the high rate of spontaneous resolution. Recurrences are exceptional, and the prognosis is generally favorable, although further studies are needed to draw definitive conclusions about its management and treatment. This article aims to summarize the currently available literature on this rare benign breast pathology, providing updated data—including immunohistochemical markers—to support clinicians in routine clinical practice.