Follicular dendritic cell sarcoma: two rare cases and a brief review of the literature

Follicular dendritic cell sarcoma (FDCS) is a rare malignant tumor recognized in recent years. It accounts for only 0.4% of soft-tissue sarcomas, and its underlying causes are largely unknown. A correct diagnosis can be difficult to make. Diagnosis of FDCS depends on the combined clinical examination, histopathologic features, electron microscopic examination and confirmation with immunohistochemical studies. Here, we report two rare cases of FDCS: one case involving multiple bones, and the other involving extensive abdominal and pelvic cavities. Clinical, histopathological, and immunohistochemical aspects, therapeutic options, and a related literature review of the two cases are discussed. As the prevalence of FDCS is increasing, the details of these rare cases may highlight the importance and facilitate treatment of similar diseases.