Fibroblastic reticular cell tumor of the breast: A case report and review of the literature.

Fibroblastic reticular cells (FBRCs) are basic mesenchymal cells that belong to the dendritic cell family. Primary extranodal FBRC tumor (FRCT) cases are rare, with only 19 cases reported in the literature thus far. However, none of these cases originated in the breast tissue. To the best of our knowledge, the present study reported the first FRCT case of the breast in a 57-year-old woman. The patient complained of a painless mass that was located in the right breast and was ~3.5×2.5 cm in size. The patient underwent modified radical mastectomy subsequent to the diagnosis of FRCT after analysis of the lumpectomy specimen. Pathological examination revealed that the tumor was mainly composed of oval and spindle cells, and was infiltrated with lymphocytes and plasma cells. The tumor cells were immunoreactive for vimentin and negative for CD21, CD35 and S-100 protein. Six axillary lymph nodes were found to have been involved. Following surgery, the patient received four cycles of mesna, doxorubicin, ifosfamide and dacarbazine regimen chemotherapy (70 mg adriamycin day 1; 2.0 g ifosfamided days 1-3; 0.4 g dacarbazine day 1-3), which cycled every 21 days. The patient was uneventfully followed-up for 20 months following chemotherapy. In conclusion, the present study reported what appeared to be the first case of primary breast FRCT. The diagnosis, treatment and prognosis details presented in this study will help improve the diagnosis of the disease.