Multidisciplinary Cancer Investigation

Introduction: Dermatofibrosarcoma protuberans (DFSP) is an intermediate and slowgrowing sarcoma, developing most commonly in the trunk and extremities and rarely in the breast. It may be recurrent, but metastasis is not common. Excisional surgery with enough resection margins decreases the recurrence rate much more.
Case Presentation: An 18-year-old woman presented with posttraumatic bruising of the right axilla near her breast which had been converted to a nodular mass. A well-defined firm mass, fixed to the dermis, palpable with mild tenderness, was present. Ultrasound (US) revealed a cyst with thickened wall, internal echo septa and high vascularity. The findings were suggestive of a complex cyst or infected epidermal inclusion cyst (EIC). Pathological investigation revealed uniform spindle cells in a storiform arrangement. In immunohistochemistry (IHC), tumoral cells showed reactivity for CD34 and the diagnosis of DFSP was made.
Conclusion: Various breast lesions including cysts as well as benign and malignant masses may show similar appearance in imaging studies, which makes clear the crucial role of the pathological and immunohistochemical investigations to confirm a definite diagnosis.