247 A Unique Presentation of Fibrosarcomatous Dermatofibrosarcoma Protuberans of Breast: A Case Report. (11th January 2018) - Hameed, Nadia
Abstract: Introduction: Dermatofibrosarcoma protuberans (DFSP) is a rare metastasizing mesenchymal tumor of the deep dermis and subcutaneous tissue. While it frequently occurs in the trunk and extremities, breast involvement has rarely been reported. A preoperative diagnosis of DFSP is extremely difficult because it is a very rare entity, and its appearance is often similar to that of benign breast lesions. Methods: The patient is a 34-year-old African-American woman, who presented with a slow-growing mass in her left breast for the past 2 years with a rapid increase in size over the past 4 to 5 months. Physical examination revealed a cystic lesion with fluctuant center and peripheral induration at the inferior aspect of the left breast. The CT scan revealed a subcutaneous ovoid lesion with increased attenuation in the inferior aspect of the left breast measuring 7.1 cm, most consistent with a sebaceous cyst, abscess or breast mass. The entire mass was excised and submitted for histological diagnosis. Microscopic examination showed a well demarcated tumor involving the dermis and infiltrating the subcutaneous tissues forming a 7.5 cm mass consisting of spindle cells arranged in a storiform pattern and short fascicles. Fibrosarcomatous transformation was identified as hypercellular spindle cells in a herringbone pattern with marked nuclear atypia, necrosis, and mitotic activity (5 MF/10 hpf). Margins were extensively involved. The tumor cells were positive for CD34 and vimentin. The final diagnosis was fibrosarcomatous DFSP. FISH revealed rearrangement of PDGFB gene. Conclusion: Our present case highlights a rare presentation of DFSP in breast with fibrosarcomatous changes. Wide local excision remains the gold standard of treatment. This tumor has high recurrence rate, and if associated with fibrosarcomatous transformation, aggressive long-term follow-up is recommended. Tumors with rearrangement of PDGFB gene including t(17;22) have been shown to be sensitive to tyrosine kinase inhibitors.