Abstract
Follicular dendritic cell sarcoma (FDCS) is an uncommon malignant neoplasm that arises from follicular dendritic cells (FDCs). The mediastinum is a more unusual site of FDCS. In this document, we detail a case involving the complete surgical removal of FDCS located in the mediastinum. A 28-year-old woman presented with symptoms of right chest pain. Accompanying symptoms include chest tightness, shortness of breath, and faintness. Chest computed tomography was performed and revealed abnormal enhancement in the mediastinal region. An excisional biopsy was carried out, and through the aid of immunohistochemistry (IHC), a diagnosis of FDCS was confirmed. Following surgery, the patient underwent radiotherapy for 27 sessions. The patient was followed up by the oncology service for 6 years and was still alive at the time of drafting this report. This exceedingly uncommon case underscores the challenges in making a differential diagnosis and emphasizes the significance of diagnostic indicators, including histopathology and IHC, in establishing a diagnosis. Clinicians should be alert to the possibility of encountering this disease and take into consideration various characteristics to avoid misdiagnosis.