Solitary fibrous tumor of the breast

A solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm that was first documented in pleura, but ubiquitous in nature, involving extrapleural sites such as the upper respiratory tract, mediastinum, head and neck. To date, about 21 cases of SFT of the breast have been reported. Herein, we presented a 60-year-old Korean female with a palpable mass in the left breast. Ultrasonography with near-oval shape, and well-circumscribed margins suggested a benign lesion, so complete resection was performed. With immunohistochemical staining, we could obtain a definitive diagnosis. Since some SFTs have unpredictable clinical course, long-term follow-up is needed for all patients.