Dermatofibrosarcoma Protuberans of the Breast: Radiologic-Pathologic Correlation

Dermatofibrosarcoma protuberans (DFSP) is a rare, locally aggressive, low-to-intermediate grade fibroblastic neoplasm arising from the skin that can uncommonly involve the breast and mimic primary breast malignancy. Dermatofibrosarcoma protuberans of the breast typically presents as a palpable, slow-growing superficial mass with an associated flesh-colored or red-brown skin lesion. On mammography, DFSP most often demonstrates an oval, circumscribed, equal or high-density mass. Ultrasound typically shows an oval hypoechoic or heterogeneous circumscribed mass, frequently with internal hypervascularity. MRI commonly demonstrates a superficial mass without circumscribed margins, with T1 hypointensity, T2 hyperintensity, and avid heterogeneous or homogeneous enhancement. Histologically, DFSP demonstrates uniform spindle cells in a storiform pattern with infiltrative extension into subcutaneous fat; immunochemistry is characteristically CD34-positive. Molecular testing can confirm the diagnosis by identifying a platelet-derived growth factor receptor Beta (PDGFB) fusion (classically collagen type I alpha 1 gene [COL1A1]: PDGFB) and may be helpful in limited sampling or atypical morphology. Treatment is complete surgical resection with negative margins, with re-excision for positive margins. Although local recurrence can occur, metastasis is uncommon, and long-term disease specific survival is excellent. Careful radiologic-pathologic correlation facilitates accurate diagnosis, concordance assessment after biopsy, and appropriate management.